






































Office and Laboratory 

159 Pierpont Avenue 
Salt Lake City, Utah 


* 


















































































Metallurgical Bulletin 


The Genera / Engineering 

Company 

(Incorporated) 

Consulting Engineers 


OFFICERS 


J. M. CALLOW 
ERNEST GAYFORD 
KARL BERNSON 
JAS. W. NEILL 
C. E. CHAFFIN 


President and Gen. Manager 
Vice-President and Secretary 
Director 
Director 
Director 


"7 7- v 6 ^ v 

Salt Lake City, Utah New York City 

159 Pierpont Ave 120 Broadway 

U. S. A. 

Copyright 1922 

by The General Engineering Company 


JAN 13 1922 






ACKNOWLEDGMENTS 

In a publication of this nature, use is made of data from a variety 
of sources, and it is our desire that full credit be given. Some material is 
obviously of a public nature and it is tpiite impossible to give credit to 
the originator, but where the information has been taken bodily or adapt¬ 
ed from published tables credit is given with our table. 

Use has been made of matter published in the bulletins of the Ameri¬ 
can Insitute of Mining and Metallurgical Engineers, the Institute of 
Mining and Metallurgy, the U. S. Bureau of Mines, the U. S. Geological 
Survey, and other governmental bureaus; the Engineering & Mining Journal, 
the Mining and Scientific Press, Richard’s Ore Dressing, Allen’s Handbook 
of Ore-Dressing, various engineers-handbooks, manufacturers catalogs, etc. 

Much of the data has been accumulated by the General Engineering 
Company in the course of its many years service, and much has been 
worked up for this bulletin. 

Use has been made of some of the illustrations in Agricola’s De Re 
Metallica made available by the translation and publication of Herbert 
Clark Hoover and Lou Henry Hoover. 



A654902 

























































































































































CONSULTING ENGINEERS 


5 


METALLURGICAL BULLETIN 


Successful mining depends upon profitable marketing of the 
products of the operations. 

The very nature of ores, with the great variation in minerals, 
economic metals, refractory elements, grain sizes, physical proper¬ 
ties, etc. makes its beneficiation more than a simple process. 

All ores require treatment in a metallurgical plant before 
ihe products can be profitably marketed. 

Successful metallurgical plants are predicated upon forehand 
knowledge of the behavior of the ore and its constituents under 
various treatments and conditions, worked out into a comprehensive 
plan or flow-sheet, and embodied in a design which utilizes the 
best of modern machinery and appliances to obtain the desired 
products with the minimum of operation difficulties and at min¬ 
imum cost. 

The business of the General Engineering Company is the work 
of putting mines upon an economical producing basis:— the exam¬ 
ination of mines to determine those factors affecting production ; 
sampling the mine for ore treatment; analysis and testing of ores, 
planning for economical recovery of the values; design of metal¬ 
lurgical plants based upon the results of metallurgical tests; pur¬ 
chase of equipment; erection and operation of plants; sampling 
and sale of metallurgical products; and solution of such engineer¬ 
ing, metallurgical and economic problems as naturally arise in 
these connections. In addition, the plant and staff have served 
and will continue to be available for the solution of similar prob¬ 
lems in industrial work. 

The General Engineering Company was organized in 1905 with 
a strong engineering staff and a laboratory for testing ores. The 
original organization is practically intact, with such additions as 
naturally come to a business whose continued success demands the 
broadening and strengthening of its lines and the extension of its 
facilities. While the offices and testing plant are still in their 
original location, both have been more than doubled in floor space 
in the last few years. 

John M. Callow, as president, has had the direct management 
of the company since its inception. The mining public is well 
aware of his international reputation as an expert in ore-treat¬ 
ment problems, and in the design of metallurgical plants and equip- 







6 


THE GENERAL ENGINEERING COMPANY 


ment. He has developed Pneumatic Flotation, and it is largely 
to his efforts that the great success of this process is due. The 
Callow Tank and Callow Traveling Belt Screen are also success¬ 
ful machines of his invention. 

Mr. Callow divides his time between the Salt Lake and the 
New York offices of the company. 

The other officials of the company are well-known men of 
technical training and years of practical experience. 



Testing Plant 

Concentrating Tables, Callow Tanks 


Recognition of a world demand for the services of the General 
Engineering Company, as well as from engineers and operators of 
the eastern United States, led to the establishment of an office 
in New York City. The coordination of our two offices is quite 
thorough ; Mr. J. M. Callow spending a part of his time at each of¬ 
fice, and by a system of exchange of correspondence and data, full 
information regarding progress of all work and new developments 
are made available at both offices. 







CONSULTING ENGINEERS 


7 


In these times of rapid advance in the science and art of ore 
treatment and allied subjects, it is necessary to keep closely in 
touch, not only with new processes, but with new types of machin¬ 
ery. 1 lie General Engineering Company aims to be progressive ; 
it has always been willing to spend the necessary time and money 
to investigate thoroughly such processes and equipment as in its 
judgement might be of value to its clientele, that it may be able 
to advise them of their merits. 



Testing Plant 

Tonnage Pneumatic Flotation Equipment 
Jigs in background. 


Modern plants make use of the pebble, ball, and rod mills for 
the finer crushing operations. The development of the pebble mill 
as a granular crusher for concentration was started in the testing 
laboratories of the General Engineering Company; it was among 
the first to adopt the ball mill for wet crushing. Rod mills and 
other improvements are being carefully investigated for the benefit 
of its clients. 

































8 


THE GENERAL ENGINEERING COMPANY 


Flotation, the most important metallurgical process of recent 
years, lias made tremendous strides since the General Engineering 
Company built the first Pneumatic Flotation plant in 1914. Par¬ 
ticular attention has been given to the perfection and commercializ¬ 
ing of special and new dotation reagents, and its laboratory is 
equipped to deal with dotation problems of any nature. 

Some of the leaching processes have great commercial pos¬ 
sibilities on ores and concentrated products. Leaching with acids 
and alkalies, sulphatizing roasting with leaching, etc. show prom¬ 
ising results, both in the laboratories of the General Engineering 
Company and in several commercial plants. 

Investigation of new processes and new types of machinery 
is a specialty, for which the General Engineering Company’s lab¬ 
oratories are particularly well equipped. A number of well known 
successful machines, devices and processes have been developed 
in these laboratories, under its supervision, or with its advice as 
consultants. 

The sale of ore-shipments with the attendant supervision of 
sampling is done for clients unable to attend to such matters them¬ 
selves. Familiarity with local samplers and smelters, ore sched¬ 
ules, etc, qualify the General Engineering Company peculiarly to 
safeguard their interests. 


MINE EXAMINATION WORK 

Before a mine can be valued or put into production, the eco¬ 
nomic method of treatment of its ore must be known. Likewise, 
before a treatment process can be worked out, the mine itself must 
be studied, for character of ore bodies, tonnage of ore available, 
determination of shipping ore, milling ore, and waste; all these 
have an economic bearing upon the property. 

It follows logically that the examination and valuation of 
mines and the treatment of the ores are so closely related, that 
best results are obtained by the use of one organization for this 
work. 

The General Engineering Company is affiliated with ex¬ 
perienced mining engineers, and is prepared to undertake mine ex¬ 
aminations and reports, in connection with proposed treatment 
plants, or for other purposes, as desired. 

DEVELOPMENT OF PROSPECTS AND SMALL MINES.— 
The supervision of the development of smaller mining properties, 
aiming at the opening of such ore-bodies as may be made com¬ 
mercial by shipment or milling will be undertaken. 









Testing Plant The General Engineering Co., Salt Lake City, Utah 































































































































































































































































































































— /yxsTfioox Pin* — 










































































































































































































































































































































































CONSULTING ENGINEERS 


9 


ORE TESTING 

Mill operations can be expected to be successful only when 
the design of the plant is suitable to the ore to be treated. Ac¬ 
curate and complete data for the design of treatment plants for 
ores can only be obtained in a suitably equipped testing plant. 
The Ore Testing Plant of the General Engineering Company is 
generally recognized as the best equipped and the most practical in 
the entire world; on the results of its testing, a large number of 
successful plants have been built. 


DESIGN OF TESTING LABORATORY 

The Ore Testing Laboratory of the General Engineering 
Company is unique and differs from other plants of similar nature 
in that actual mill conditions are here duplicated, the process of 
whatever character being continuous and not intermittent. This 
plant is so arranged that all possible ore dressing combinations 
can be made at will, the ore starting at the feeder and progressing 
through, from machine to machine, in exactly the same manner 
as if it had been especially built for the particular ore. 

The laboratory covers two floors, each 20x120 feet, and part 
of an upper floor, 20x30 feet. The arrangement, variety and char¬ 
acter of equipment, and the exceptional facilities will be better 
comprehended from an examination of the line drawings inserted 
here. As new machines are perfected and new processes commer¬ 
cialized, the General Engineering Company aims to include 
in its laboratory such new machines and such necessary equip¬ 
ment for new processes wherever possible; it is only by keeping 
up-to-date that the best service can be given. 


METALLURGICAL TESTS 

These divide naturally into three classes: 

Preliminary Investigation Tests 

Complete Metallurgical Tests 

Tonnage Check Tests , 

In addition, Operating Tests may be desirable, either in a leased 
commercial plant, or in a new Pilot Plant. 

It was formerly the custom to divide this metallurgical test¬ 
ing into three classes: Short Cut Tests, Preliminary Tests, Ton¬ 
nage Tests; to some extent we follow this practice in special 




10 


THE GENERAL ENGINEERING COMPANY 


cases. Long experience has brought increased confidence in the 
ability to attain in the smaller quantity tests the results obtained 
in the tonnage tests; as check results between the two show. 
The new system of tests ofifers the client in the Complete Metal¬ 
lurgical Test nearly all the information which was formerly ob¬ 
tained onlv by the Tonnage test. 

J J o 



Testing Plant 

Flotation and Gravity Concentration Equipment. 


PRELIMINARY INVESTIGATION TESTS are made upon 
small samples, of from 50 to 100 pounds, to determine in a gen¬ 
eral way what process of milling is likely to be most applicable 
to the ore in question. Detail is not gone into and the report 
gives only an outline of the methods employed and the results 
obtained. 


















CONSULTING ENGINEERS 


11 


COMPLETE METALLURGICAL TESTS are what the term 
implies, and, except where the client specifies the method or flow¬ 
sheet, the sample is subjected to any or all of the established 
processes that could be considered applicable. The General En¬ 
gineering Company’s reports are very complete and detailed, gen¬ 
erally accompanied by a flow-sheet, diagramatically illustrating the 
method of treatment employed to obtain the results shown in the 
reports; each sample and product from the test is given an indi¬ 
viduality and identity of its own, and its importance or insig¬ 
nificance becomes at once apparent. 

TONNAGE CHECK TESTS are made to establish the physical 
behaviour of the ore under conditions more nearly approaching 
practice. When satisfactory results are obtained with the smaller 
Complete Metallurgical Test, the Tonnage Check Test becomes 
unnecessary in many cases; however for such cases as appear to 
reciuire the Tonnage Check Test, the necessary equipment is main¬ 
tained in these laboratories. 

OPERATING TESTS.—In addition to the laboratory tests out¬ 
lined, it may be desirable, in certain cases, to make use of an oper¬ 
ating mill and to treat several thousand tons of ore, following out 
the flow-sheet determined in the testing plant.. 

The General Engineering Company will take charge of such 
operations, recording all the information obtained, and furnishing 
a comprehensive report. 

PILOT PLANT.—These are experimental operating plants built 
at the property, and are justified only when the ultimate erection 
of a reasonably large plant is contemplated, say of a daily capacity 
of 500 tons or more. Its capacity will depend upon local con¬ 
ditions at the property, but it should be large enough so that oper¬ 
ating conditions and costs will be comparable to those of a full 
size commercial plant. With a capacity of 50 tons per day of 24 
hours, the pilot plant should contribute materially to its support; 
and much of the machinery can be used afterwards in the com¬ 
mercial plant. 

The General Engineering Company is prepared to design, erect 
and operate such pilot mills or experimental plants. 

Information Required 

In order to show the full commercial significance of the re¬ 
sults obtained in the tests, the final deductions are usually report¬ 
ed in their money return per ton of crude ore treated, after sub¬ 
tracting all expenses and costs of milling, hauling, railroad 
freights and smelting. To do this correctly, it is necessary that 




12 


THE GENERAL ENGINEERING COMPANY 


there be furnished information as to: 

Cost of hauling from mill to nearest R. R. station, 
Freight Schedules, 

Ore Schedule under which the mill products would be sold. 



Testing Plant 

Cyanide Equipment, consisting of 
Leaching Tank, Agitating Tank, Solution Tank, Filter Press, Zinc 

Boxes, and Sumps. 


As local conditions often have a direct bearing upon the best 
treatment for an ore, information should also be furnished as to: 
Cost of labor, wages, etc. 

Cost of power, fuel, etc. 

Water Supply. 

Such information is naturally considered of a private nature. 

If a smelter schedule has not previously been obtained, the 
General Engineering Company will obtain an analysis of the 
products to be sold and will assist in obtaining the most favorable 
terms from the ore buyers. 














CONSULTING ENGINEERS 


13 


QUANTITY OF ORES REQUIRED FOR TESTS 

For Preliminary Investigation, 50 to 100 pounds. 

For Complete Metallurgical Tests, 350 to 500 pounds. 

For Tonnage Check Tests, from 3 to 5 tons, depending upon 
the flow-sheet as determined by previous investigation. 


SHIPMENTS 

All shipments should be consigned prepaid to the General 
Engineering Company, 159 Pierpont Avenue, Salt Lake City, Utah, 
mailing us bill-of-lading or express receipt. 

In case of tonnage shipments that are to be sampled by the 
public sampler, notify us before shipment, and mark the bill-of- 
lading u To be sampled in transit.” 


ASSAYING 

The General Engineering Company do no assaying them¬ 
selves; all work and reports are based upon the assays and chemical 
analyses of public and independent assayers. Before starting upon 
test work, the client is requested to designate such assayers in 
Salt Lake City as they may prefer, only the actual cost of the as¬ 
saying being charged. 


CHARGES FOR TEST WORK 

The exact cost of a test cannot be stated in advance, as it 
depends upon how much work has to be done to reach definite 
conclusions and to make final recommendations. Charges range 
from $150 to $250 for preliminary investigation, from $350 to $750 
for complete metallurgical test, and up to $1000 for tonnage check 
tests 

Conditions governing the operating tests vary to such a 
degree that it is impossible to give any estimated figures that 
would apply in specific cases. The charges in all cases are made as 
low as is consistent with good and thorough work. Anyone at 
all familiar with this class of work will realize that much time and 
care must be expended upon it, and that the renumeration should 
be commensurate. 

Clients, when applying for terms, should roughly outline the 
character of the ore. the class of test, and give all information 
available with regard to the ore as affecting the test work; an 
approximate cost for the work can then be submitted by the Gen¬ 
eral Engineering Company . 





14 


THE GENERAL ENGINEERING COMPANY 



Miniature Ore Testing Plant 

This is a complete, self-contained Ore Testing Plant consisting 
of:'2 compartment 4"x6" jig; 12"x24" concentrating table; 3 spigot 
hydraulic classifier; automatic feeder; 34 H. P. motor; piping, belt¬ 
ing, etc. 

We have supplied many of these minature ore testing plants to 
universities and mining companies all over the world. If interested 
write for special bulletin. 





















CONSULTING ENGINEERS 


15 


Consulting and Special Work 

As stated in the introduction, the General Engineering Com¬ 
pany is concerned principally with the work of putting mines 
upon an economical producing basis. 

As Consulting Engineers, the General Engineering Com¬ 
pany advise upon the many special problems that come up in 
connection with mining and the industries associated with it; 
problems requiring inspection, investigation, research, special 
designing, etc. 

While the General Engineering Company has exceptional 
facilities for research, wide experience and a competent staff, it 
does not hesitate to go outside its own organization when there¬ 
by the interests of its clients are better served. It has close as¬ 
sociation with engineer^, operators, and metallurgists, well- 
known and thoroughly experienced in those allied lines of in¬ 
dustry and practice which lie outside the regular field of the Gen¬ 
eral Engineering Company. 

Similarly, special work has recently been done by this or¬ 
ganization in such fields as: sugar refining (both beet and cane), 
phosphate and potash production, sewage disposal, thickening and 
filtration of difficult materials, roasting-and-leaching, new proces¬ 
ses, etc. 


FLOW SHEETS OF MILLS 

The purpose of ore-testing work is two-fold : (a) to determine 
whether the ore may be treated at a profit, and (b) to find the 
process whereby the most profit may be obtained. 

An ore-treatment process is best explained and comprehended 
by means of a Flow-Sheet and where considered necessary a flow¬ 
sheet accompanies the ore testing report. 

The flow-sheet is the basis upon which new plants are de¬ 
signed, and aims to show the movement of the various constitu¬ 
ents of the ore stream from the time it enters until it leaves the 
mill; quite frequently there is added information in the way of 
quantities and assays of the various constituents or products, 
and the flow-sheet may include a water chart. 

The varied characters of ores and their required treatment 
methods can be shown in no better manner than in the variation 
in the flow-sheets illustrated on the pages following. In the 
hundreds of flow-sheets in the test-report files of the General En¬ 
gineering Company, very few are alike, indicating that require¬ 
ments and conditions vary from mine to mine, and emphasizing 
the necessity for testing all ores, rather than depending upon the 
flow-sheet of an adjoining or similar property for the design of 
contemplated plants. 

Various types of mills are illustrated by the flow-sheets on 
the pages which follow. 






16 


THE GENERAL ENGINEERING COMPANY 


Copper Ore, all Flotation 




























































































































CONSULTING ENGINEERS 


17 


Gravity Concentration and Flotation 




































































































18 


rHE GENERAL ENGINEERING COMPANY 


Complex Ore, All Flotation 


cRusneo o»et oik 




lotko n?t a FLOW SHEET test yp.i?. 


GENERAL ENGINEERING CO CONSULTING ENG RS 

SALT LAKE ClTT - UTAH 
OATt JAN 2C-I92I. 



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tjk y« /nroJ 
IM % 5 


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t s 


7- Fe 
7. In so/ 




















































































CONSULTING ENGINEERS 


Lead or Copper, All Flotation 



19 





















































































20 


THE GENERAL ENGINEERING COMPANY 


Lead-Zinc Ore, Gravity Concentration and Flotation 



71 ?//* 





























































































































































































































CONSULTING ENGINEERS 


21 


Cyanide, Counter-Current Decantation 


























































































































22 


THE GENERAL ENGINEERING COMPANY 



Concentrator—Gravity and Flotation 

C. C. Cunningham, Sandon, British Columbia. 
Designed and built by the General Engineering Company. 














CONSULTING ENGINEERS 


23 


Design, Erection, Operation 

I he results of the testing work and other investigations in¬ 
dicating that the ore may be mined, treated and disposed of at 
a reasonable profit, the obvious thing is to design and erect a plant 
suitable for the ore, so that operations may be begun at an early 

date. 



First Pneumatic Flotation Plant in the World 

National Copper Company, Mullan, Idaho. 
Designed and built by the General Engineering Company 


The General Engineering Company maintain a staff particu¬ 
larly well fitted by both technical training and experience to deal 
with the problems of design. With the test results before them, 
and such necessary data and decisions as to capacity, water sup¬ 
ply, source of power, available sites, etc., the engineers make pre¬ 
liminary studies, designs and estimates for plants to give the de¬ 
sired metallurgical results. After staff consultation, such modi- 
fiations as are deemed advisable are made, and the results embodied 












24 


THE GENERAL ENGINEERING COMPANY 


in a report; a conference is held with the clients and decisions ar¬ 
rived at as to the design and other details. 

A complete set of working drawings is prepared, specifica¬ 
tions for machinery and building material are gotten out, the 
the equipment is ordered, and preparations are made to erect the 
plant. 

The General Engineering Company supply a Superintendent 
of Construction who remains at the property during the construc- 



jj 

1 VS 

’ a. 

JPI IP ” 



I*#!? <SSS 


f > !i n 


UK ' 


R t lilui 




mmrn 


Concentrator . 

Utah-Apex Mining Company, Bingham, Utah. 

Redesigned and rebuilt by the General Engineering Company 

tion period; he, together with staff engineers, in collaboration 
with the management and engineers of the mining company, all 
working together, make up an organization which is efficient 
from the start; the work progresses smoothly to completion. 

Once the enterprise is financed and the decision made to build 
the plant, good business demands that the plant be operating as 
soon as possible. Here the interests of the client and the Gen¬ 
eral Engineering Company are identical, for its reputation for 
exceptional service is one of its greatest assets 































CONSULTING ENGINEERS 


25 


This exceptional service covers: economical design, the spend¬ 
ing of no more money than is necessary for low operating costs 
and for the saving of only such values as can be saved at a profit; 
rapidity of construction, by proper planning and specifying, so 
that material is gotten on the ground when needed and the work 
of erection is expedited; efficient and competent supervision, in¬ 
suring readiness-to-run with a minimum of changes. 

The charges made by the General Engineering Company are 
based upon the cost of the work involved, and will be found reas- 



Gravity Concentration and Flotation 

Magma Copper Company, Superior, Arizona 
Designed and built by The General Engineering Company 

onable for the services rendered. Local conditions and expenses 
incident to work in different localities vary so widely that no defi¬ 
nite figures can apply to all cases. In general, the fee to cover 
the design and superintendence of erection of metallurgical plants 
will be in the neighborhood of 10% of the cost of the work. 

The fee for the operation of metallurgical plants is usually 
upon a per diem or monthly basis, and depends upon the char¬ 
acter of the work involved. 












26 THE GENERAL ENGINEERING COMPANY 


Representative Mills 

Designed and Constructed by 

The General Engineering Company 

Hecla Mining Company Wallace, Ida. Ore Sorting Plant 


Imlay Mining Company Imlay, Nev. 

Jennie Gold Mining Co. Good Springs 

Nev. 


Amalgamation—Cyanide 


Pulaski Minerals Co. 


Ketchum, Ida. 


Amalgamation— Gravity 
Concentration 


Tomahawk Mines Co. 


Durango, Colo. Amalgamation—Gravity 

Concentration— Cyanide 


Bingham & New Haven Bingham, Utah. 
G. & C. Co. 

Yukon District G. M. Co. Alaska 
Conrad Cons, Mines Co. Alaska 
Iron Mountain Tunnel Co. Iron Mtn., Mont. 
Phoenix Mining Co. BinghanL. Utah. 

Rico-Wellington Mines Co. Rico, Colo. 

Utah Apex Mining Co. Bingham, Utah. 

Watters Tunnel & Mining Sheridan, Mont. 
Co. 

National Copper & Pyrite Pyriton, Ala. 

Co. 


Gravity 

Concentration 


Glasgow & Western Expl. 
Co. 


Cherry Creek, 
Nev. 


Gravity Concentration— 
Cyanide 


Winnemucca Mountain 
Mining Co. 


Winnemucca, 

Nev. 


Cyanide 


Dominion Molybdenum Co. 
American Graphite Co. 

Steel Alloys Co. 

Vermont Copper Co. 
Molybdenum Products Co. 
Bingham & New Haven G. 

& C. Co. 

Caldo Mining Co. 

National Copper Co. 

Carbon Mountain Graphite 
Co. 

Utah Cons. Mining Co. 


Quyon, Quebec 
Ticonderoga, 

N. Y. 

Canada 

(molybdenum) 

S. Statford, Vt. 

Wilberforce, Ont. 

Flotation 

Bingham, Utah 
Frisco, Utah 
Mullan, Ida. 

Lineville, Ala. 

Tooele, Utah 


Armstead Mines Inc. 
Cons. Copper Mines Co. 


Talache, Ida. Flotation—Gravity 

Kimberley, Nev. Concentration 


Cia. Huanchaca de Bolivia Pulcayo, Bolivia 



CONSULTING ENGINEERS 


27 


Amalgamated M. & S. Corp. Pioche, Nev. 


Magna Copper Company 

Magna Copper Company 

C. C. Cunningham 
Noble Five Mine 


Superior, Ariz. 

(copper) 
Superior, Ariz. 
(zinc) 

Sandon, B. C. 
Sandon. B. C. 


El Rayo M. & D. Co. 


Parral, Mex. 


Gravity 

Concentration— 
Flotation 


Flotation—Cyanide 


Ivnight-Christensen Metal Silver City, Utah Roasting—Acid Leaching 

Co. 


Tomboy Gold Mines Co. 


Telluride, Colo. Roasting—Magnetic Sepa¬ 

ration. 



Pneumatic Flotation Plant 

Consolidated Copper Mines Co., Kimberley, Nev. 
Redesigned and rebuilt by the General Engineering Company 
















28 


THE GENERAL ENGINEERING COMPANY 


METAL STATISTICS 


The data contained in this section has been obtained from a variety of 
sources considered reliable. 

“Round Numbers” are used and slight liberties have been taken with 
some of the statistics; it is believed that in the form here presented they 
will be found most serviceable. 

Where possible, “foreign ores smelted in the U. S.” have been omitted 
from U. S. production. 


Aproximate Averages 


For 20 years up to 1920. 


Metal 

World 

Production 

Per Year 

United States 
Production 

Per Year 

%of 

World 

Prices 
f. o. b. 

New York 

Gold 

Silver 

Copper 

Lead 

Zinc 

19,000,000 oz. 
188,000,000 oz. 
1,910,000,000 lbs. 
*2,200,000,000 lbs. 
*1,790,000,000 lbs. 

4,400,000 oz. 
61,000,000 oz. 
1,120,000,000 lbs. 
*838,000,000 lbs. 

* 692,000,000 lbs. 

23 

31 

59 

*38.1 

*38.6 

$20.67 per oz. 
0.61 per oz. 
0.18j per lb- 
0.053 per lb. 
0.074 per lb. 


* For 17 years 1904 to 1920. 


Gold and Silver 

Production—United States and World 



GOLD 




SILVER 


$20.67 per oz. 






i 

United States 



United States 


Ave. 



World • 

Year 



World 

Price 

Millions 

% World 

Millions 


Millions 

% World 

Millions 

per 

Dollars 


Dollars 


Ounces 


Ounces 

Ounce i 

79.2 

31.1 

254.6 

1900 

57.6 

33.1 

173.6 

$0.62 

78.7 

30.2 

261.0 

1901 

55.2 

31.9 

173.0 

.60 

80.0 

27.0 

296.7 

1902 

55.5 

34.1 

162.8 

.53 

73.6 

22.5 

327.7 

1903 

54.3 

32.4 

167.7 

.54 

80.5 

23.2 

347.4 

1904 

57.6 

35.1 

164.2 

.58 

88.2 

23.4 

380.3 

1905 

56.1 

32.5 

172.3 

.61 

94.4 

23.4 

402.5 

1906 

57.5 

34.2 

165.1 

.68 

90.4 

21.9 

413.0 

1907 

56.5 

30.3 

186.2 

.66 

94.6 

21.3 

442.5 

1908 J 

52.4 

25.8 

203.1 

.53 

99.7 

21.9 

454.1 

1909 

54.7 

25.8 

212.1 

.52 

96.3 

21.1 

455.2 

1910 

57.1 

25.8 

221.7 

.54 

96.9 

21.2 

461.9 

1911 

60.4 

26.7 

226.2 

.53 

93.5 

20.1 

466.1 

1912 

63.8 

28.4 

224.3 

.615 

88.9 

19.3 

460.5 

1913 

66.8 

29.7 

225.4 

.604 

94.5 

21.5 

439.0 

1914 

72.5 

43.0 

168.5 

.553 

101.0 

21.6 

468.7 

1915 

75.0 

40.7 

184.2 

.507 

92.6 

20.4 

454.2 

1916 

74.4 

44.1 

168.8 

.658 

83.8 

20.0 

419.4 

1917 

71.7 

41.1 

174.2 

.824 

68.6 

18.0 

380.9 

1918 

67.8 

34.3 

197.4 

.98 

60.3 

16.5 

365.1 

1919 

56.7 

32.7 

174.5 

1.12 

49.5 



1920 

56.6 



1 015 



























































CONSULTING ENGINEERS 


29 


Copper 

Smelter Production—United States and World 


Year 

World 

Produc¬ 

tion 

Millions 
of lbs. 

UNITED 8iALES 

Prices 
Per lb. 
Cents 

Ores 

of Co’per 

Millions 
of Tons 

Yield 

% 

From 
Dom’s’c 
Ores 
Millions 
of lbs. 

% of 
World’s 

Ap’arent 
Con- 
sump’on 
Millions 
of lbs. 

1900 

1,091 

* 

* 

606 

55.6 

357 

16.6 

1901 

1,160 

* 

* 

602 

51.9 

383 

16.7 

1902 

1,228 

* 

* 

660 

53.6 

552 

12.2 

1903 

1,313 

* 

* 

698 

53.2 

526 

13.7 

1904 

1,454 

* 

* 

813 

55.9 

482 

12.8 

1905 

1,570 

* 

* 

889 

56.6 

581 

15.6 

1906 

1,589 

18 

2.53 

918 

57.7 

686 

19.3 

1907 

1,596 

20 

2.15 

869 

54.4 

488 

20.0 

1908 

1,651 

22 

2.12 

943 

57.1 

480 

13.2 

1909 

1,832 

28 

1.95 

1,093 

59.7 

689 

13.0 

1910 

1,901 

28 

1.89 

1,080 

56.8 

732 

12.7 

1911 

1,968 

30 

1.82 

1,097 

55.8 

682 

12.5 

1912 

2,209 

36 

1.75 

1,243 

56.3 

776 

16.5 

1913 

2,133 

36 

1.67 

1,224 

57.4 

812 

15.5 

1914 

2,023 

35 

1.60 

1,150 

56.8 

702 

13.3 

1915 

2,326 

43 

1.66 

1,388 

59.7 

1,137 

17.5 

1916 

2,994 

58 

1.70 

1,928 

64.4 

1,479 

24.6 

1917 

3,147 

59 

1.60 

1,886 

60.0 

1,395 

27.3 

1918 

3,076 

62 

1.51 

1,909 

62.0 

1,662 

24.7 

1919 

* 

* 

* 

1,311 

* 

877 

18.6 

1920 

* 

* 

* 

1,209 

* 

1,054 

18.4 


* Not Available. 

High Price (1864), 55 cents (47 cent ave.) ; Low Price (1894), 
9.00 cents (9.43 cents ave.) 


Production in U. S.—By State Groups 

Millions of Pounds 




1913 

1914 

1915 

1916 

1917 

1918 

1919 

1920 

Alaska 


23 a 

25 

71 

114 

85 

67 

57 

66 

Arizona 

New Mexico 


454 ’ 

447 

495 

775 

827 

866 

597 

605 

California 


32 

30 

38 

43 

45 

44 

24 

12 

Colorado 

^Wyoming 

Idaho 


9 

*7 

8 

9 

8 

7 

4 

2 

Oregon 

Washington 


10 

hj 

t 

8 

12 

10 

11 

9 

6 

Michigan 


156 

158 

239 

270 

269 

231 

178 

153 

Montana 


286 

237 

268 

352 

276 

326 

176 

178 

Nevada 

Utah 


233 

221 

243 

333 

343 

328 

204 

163 

Tennessee 


19 

19 

18 

15 

16 

15 

16 

17 

All Others 


1 

1 

1 

2 

1 

1 

*17 

1 


♦Including 15,500,000 lbs. undistributed. 





































3d 


THE GENERAL ENGINEERING COMPANY 


Copper 

Balance Sheet Refined Copper in U. S. 

Millions of Pounds 



On 

Refined 

in U. S. 



Exp-For 

Year 

Hand 
Jan. 1. 

Domestic 

Origin 

Foreign 

Origin 

Exported 

Consumed 

Domestic 

% 

1913 

105 

1,237 

378 

817 

812 

35.6 

1914 

91 

1,210 

323 

748 

702 

39.3 

1915 

174 

1,388 

246 

589 

1,137 

24.0 

1916 

82 

1,889 

371 

735 

1,479 

19.3 

1917 

128 

1,874 

555 

1,048 

1,395 

26.3 

1918 

114 

1,883 

550 

705 

1,662 

*8.2 

1919 

180 

1,442 

326 

440 

877 

*7.9 

1920 

631 

1,182 

453 

553 

1,054 

*8.5 

1921 

1922 

659 

384 Est. 

900 Est. 

1175 Est. 



♦Additional exports of old copper, sheets, plates, etc., for the 
years 1918, 1919, 1920 increased exports and % to the following fig¬ 
ures, respectively; 748, 10.8%; 517, 13.2%; 624, 14.4%. 


Note.—The last column, gives in percent the ratio of the dif¬ 
ference between the copper exported and that imported as foreign 
ores for smelting and refining, to the copper refined from domestic 
ores only. 'This is the actual percentage of copper produced from 
U. S. ores which is exported, without further manufacture. During 
the world war a great part of the copper produced was exported in 
manufactured form for which statistics are not available. 





















































































































































CONSULTING ENGINEERS 


31 


Lead and Zinc 


Production United States and World 


LEAD 


ZINC 

United 

States 

World 

Prices 

Year 

United 

States 

World 

Prices 

Millions 

%of 

Millions 

Cents 


Millions 

%of 

Millions 

Cents 

of lbs. 

World 

of lbs. 

per lb. 


of lbs. 

World 

of lbs. 

per lb. 

*645 

X 

X 

4.4 

1900 

*218 

X 

x 

4.4 

*650 

X 

X 

4.3 

1901 

*282 • 

X 

X 

4.1 

*645 

X 

X 

4.1 

1902 

*315 

X 

X 

4.8 

*647 

X 

X 

4.2 

1903 

*318 

X 

X 

5.4 

614 

29.5 

2087 

4.3 

1904 

*373 

27.0 

1385 

5.1 

604 

29.0 

2084 

4.7 

1905 

*407 

28.0 

1455 

5.9 

700 

33.2 

2107 

5.7 

1906 

*450 

29.0 

1550 

6.1 

730 

33.3 

2190 

5.3 

1907 

*500 

30.7 

1630 

5.9 

623 

27.1 

2300 

4.2 

1908 

*420 

26.3 

1595 

4.7 

706 

30.3 

2340 

4.3 

1909 

*512 

30.0 

1710 

5.4 

751 

31.0 

2420 

4.4 

1910 

*538 

28.6 

1885 

5.4 

784 

31.8 

2455 

4.5 

1911 

543 

27.5 

1970 

5.7 

785 

30.6 

2565 

4.5 

1912 

648 

30.3 

2140 

6.9 

824 

32.4 

2540 

4.4 

1913 

675 

30.2 

2230 

5.6 

1025 

56.0 

1828 

3.9 

1914 

687 



5.1 

1014 

44.2 

2290 

4.7 

1915 

916 

49.8 

1840 

12.4 

1102 

53.3 

2062 

6.9 

1916 

1129 

50.3 

2240 

13.4 

1097 

53.9 

2035 

8.6 

1917 

1169 

53.9 

2170 

10.2 

1080 

48.2 

2243 

7.1 

1918 

985 

51.3 

1920 

9.1 

849 

41.2 

2060 

5.3 

1919 

905 

65.1 

1390 

7.3 

954 

53.0 

1800 Est. 

8.0 

1929 

900 

60.0 

1500 Est, 

8.1 


including foreign ores smelted in U. S. 


x Figures not available. 




































32 


THE GENERAL ENGINEERING COMPANY 


COSTS 

Milling Costs 

The costs given in the following tables have been gathered 
from a variety of sources, such as published company reports, 
technical articles, handbooks, manufacturers catalogs, and pri¬ 
vate information. Usually the methods of arriving at the costs 
of the various operations and the distribution of overheads, etc., 
differ considerably, so that unless all details are known and com¬ 
parable, considerable judgement must be used in applying such 
figures. 

The only safe method of arriving at milling costs for pro¬ 
posed plants or processes is to furnish to competent engineers 
all the facts available, and let them estimate such costs. 

In plants of the same type, the large factor producing the 
wide variation in costs per ton is obviously the capacity of the 
plant, greater economies being possible in a large plant than a 
small one. 

Recent figures show increased costs because of the effects of 
the world war; it is believed that costs for the period 1912-1916 
will be of as much value as for the period 1917-1920, and that 
actual costs will be found midway between these two sets of 
figures, for the years following the publication of this bulletin. 

Tables of partial costs are given together with tables made 
up of the results of operations of individual plants. Total costs 
may be made up by totaling the partial costs, using the tables 
of total costs for the purpose of checking, and for estimating the 
effect of various variables, such as freight and transportation, 
power, labor, climate, etc. 

The value extracted from the ore is believed to have some 
bearing upon the amount that may be expended to treat the ore, 
and for that reason the production has been calculated in dollars 
extracted rather than in assays of the i mill feed. In some cases 
this figure has been roughly approximated, and it is intended to 
be used only for its bearing upon the cost, however variable that 
may be. 

In the cases of Gold and Silver mills, a study of costs indi¬ 
cated that more consistent costs were obtained by a division as 
affected largely by climatic conditions: 

DESERT CONDITIONS indicate high costs for power, 
water and transportation, with unfavorable labor, living and cli¬ 
matic conditions, or most of these. 

AVERAGE CONDITIONS indicate that there are not more 
than two of the unfavorable factors under Desert Conditions, 
the balance being normal or favorable. 




CONSULTING ENGINEERS 


33 


Costs of Mill Operations 

Flotation Concentration Mills 

Copper, Iron, Zinc 


Tons 

24-Hrs. 

Location 

Value 
Extr 
per ton 

xtrn 

% 

Treatment Details 

Cost 

Per 

Ton 

% 

-200 

Date 

Remarks 

125 

200 

400 

New York 
Arizona 

Utah 

$19 00 

93 

Cr. Ball. Flot 

Cr. Ball. Tab. Flot. 

Cr. Rolls Ball. Jig. Tab. Flot 

$1.31 
0.87 

45 

1919 

1916 

Lead 

1100 

4000 

Montana 

Arizona 

19.00 

78 

Cr. Rolls. Peb. Tab. Flot. 

Cr. Rolls. Ball. Tab. Flot. 

2.75 

62 

1919 

1919 

Zinc 

Copper 

Copper 

5000 

Arizona 

9.00 

78 

Cr. Rolls. Ball. Tab Flot. 

0.73 

60 

1918 

5000 

Arizona 

5.80 


Cr. Rolls. Ball. Tab. Flot. 

1 01 


1919 

Copper 

10000 

New Mexico 

7.00 


Cr. Rolls. Ball. Tab. Flot. 

1.37 


1918 

Copper 

12000 

Nevada 

6.40 

68 

Cr. Rolls. Ball. Tab. Flot. 

0.93 


1918 

Copper 

12000 

Utah 

5.00 


Cr. Rolls. Ball. Tab. Flot. 

0.93 


1918 

Copper 

15000 

Arizona 

5.66 

75 

Cr. Pis'\ Ball. Flot. 

0.53 

60 

1916 

Copper 


Gravity Concentration Mills 

Lead, Copper, Zinc 


Tons 

24-Hrs. 

Location 

Value 
Extr 
per ton 

xtrn 

% 

Treatment Details 

Cost 
Per 
To n 

% 

-200 

Date 

Remarks 

125 

Utah 




$1.44 


1912 


150 

Utah 




1.09 


1917 


200 

Utah 



Sort. Cr. Roll. Cone. 

0.58 


1912 


300-400 

Missouri 



Cr. RoH. Jigs. 

0.41 


1913 

Zinc 

400 

Colorado 

$6.50 


Cr. St. Peb. Cone. 

2 08 



Cyaniding Concentrates 

500 

Missouri 


Cr. Roll. Jig. Tab. 

0 97 


1912 

500 

Idaho 



0.5; 


1919 


1000 

Idaho 

11.00 

91 

Cr. Roll. Jig. Tab. 

0 37 


1908 

Lead-Silver 

1000 

Idaho 

17.00 


Cr. Roll. Jig. Tab. 

0.71 


1918 

Lead-Silver 

1250 

Idaho 



Cr. Roll. Jig. Tab. 

0.3( 


1911 

Lead-Silver 

1250 

Missouri 



Cr. Roll. Jig. Tab. 

0.3. 


1912 

Lead 

2500 

Missouri 



Cr. Roll. Jig. Tab. 

0 26 
0.34 


1913 

Lead 

3300 

Arizona 

4.80 

70 

Cr. Roll. Ch. Tab. Van. 

0 57 


1912 

Copper-Disseminated 

4500 

New Mexico 

3.40 

70 

Cr. Roll. Tab. Van. 

0.50 


1912 

Copper-Dissemintaed 

6500 

Arizona 

3.15 

67 

Cr. Rolls. Tab. Van. 

0.4. 


1913 

Copper-Disseminated 

8000 

No.vada 



Cr. Rolls. Tab. Van. 

0 49 


1912 

Copper-Dissemintaed 

21000 

Utah 

2.30 

66 

Cr. Rolls. Tab. Van. 

0.31 


1913 

Copper-Disseminated 

1000 

Michigan 

2to4 

70-80 

Cr. S St. Jig. Tab. 

.27-30 


1908 

Copper-Amydaloid 

2000 

Michigan 

2-4 x /2 

70-80 

Cr. S St. Jig. Tab. 

.24-30 


1908 

Copper-Amygdaloid 

4000 

Michigan 

1M3L 

70-80 

Cr. S St. Jig. Tab. 

.17-40 


1908 

Copper, A myg.&Conglom. 









Conglom Costs Highest. 


Abbreviations used in column of “Treatment Details” in all tables of 
Cost of Mill Operations:— 


CR—Crushers 

ST—Stamps 

BALL—Ball mills 

PEB—Pebble or Tube Mills 

DISC—Disc Crushers 

CH—Chilean mills 

PAN—Grinding Pans 


TAB—Concentrating tables 

VAN—Vanners 

JIG—Hartz Jigs 

FLOT—Flotation 

CONC—Gravity Concentration 

CY—Cyanide 

A M A L—Amalgamation 




































































34 


THE GENERAL ENGINEERING COMPANY 


Cost of Mill Operations 

Silver Mills-All Slime Cyaniding 


Average Conditions 


Tons 

24-Hrs. 

Location 

Value 
Extr 
per ton 

xtrn 

% 

Treatment Details 

Cost 

Per 

Ton 

07 

/o 

-200 

Date 

Remarks 

ISO 

Canada 

$30.00 

90 

Milling 

$2-?3 


1913 

Costs Roughly Approx. 

250 

Canada 


92 

Cr. St. Peb. Cy. 

2.95 

28 

1913 


350 

Canada 

10.25 

95 

Cr. St. Peb. Cy. 

2.10 


1913 


450 

Mexeo 



Cr. St. Cone. Peb. Cy. 

2.64 


1918 


500 

Canada 



Cr. Hall. Peb. Cv. 

2.64 


1919 



Silver—Desert Conditions 


Tons 

24-Hrs 

Location 

Value 
Extr 
per tofu 

xtrn 

% 

' 

Treatment Details 

Cost 

Per 

Ton 

% 

-200 

Date 

Remarks 

100 

Nevada 

$15.30 

90 

Cr. St. Peb. Cone. Cy. 

$3.29 

90 

1913 


110 

Mevada 

13 00 

94 

Cr. St. Peb. Cone. Cy. 

3.54 


1913 


130 

Nevada 

19.00 

92 

Cr. St. Peb. Cone. Cy. 

2.62 


1913 


135 

Mevada 

16.00 

93 

Cr. St. Ch. Peb. Cy. 

2.75 

69 

1914 


175 

Mevada 



Milling 

3.80 


1912 


250 

Mexico 

11.00 

93 

Cr. St. Peb. Cone. Cy. 

3.86 


1J913 


400 

Nevada 



Milling 

2.90 


1912 


500 

Mevada 

16.30 

90 

Cr. St. Peb. Cone. Cy. 

2.67 


1913 


500 

Nevada 

16 00 


Cr. St. Peb. Cone. Cy. 

2.57 


1914 


500 

Nevada 

21 00 

94 

Cr. St. Peb. Cone. Cy. 

2 05 

80 

1914 

1913. Cost $2.50 


Gold Mills—Roasting Cyanide 


Tons 

24-Hrs. 

Location 

Value 
Extr 
per ton 

xtrn 

: % 

Treatment Details 

Cost 

Per 

Ton 

% 

-200 

Date 

Remarks 

100 

550 

600 

700 

Washington 

Utah 

W. Australia 
W. Australia 

$8.00 

91 

Cr. Rols. Roast. Peb. Cy. 

Cr. Rolls. Roast. Peb. Cy. 

Cr. Rolls. Roast. Peb. Cy. 

Cr. St. Pan. Con. Roast. Cv. 

$2.00 

1 10 

2.29 

2.08 


1913 

11-12 

1913 

1912 

33% Roasted 

Cone, onlv Roasted. 

5 00 
9.50 

85-% 


Gold Mills—Amalgamation—Concentration 


Tons 

24-Hrs. 

Legation 

•• > jT«- *.i 

Value 
Extr 
per ton 

xtrn 

% 

Treatment Details 

Cost 

Per 

Ton 

% 

-200 

Date 

Remarks 

30 

50 

200 

300 

1000 

1300 

2500 

4000 

7000 

California 

California 

Korea 

California 

Alaska 

Transvaal 

Alaska 

50. Dakota 
\ la ska 

$3.00 
13 50 

90 

Cr. St. Amal. 

Cr. St. Amal. Cone. 

Cr. St. Cone. Amal. 

Cr. St. Amal. 

Cr. St. Cone. Amal. 

Cr. St. Amal. 

Cr. St. Amal. Cone. 

Cr. St. Amal. 

Cr. Rolls. Peb. Cone. 

+1 . 

1 07 
+0.67 

+0.22 
0 24 
+0.27 

0 185 
+0.28 
0 24 

35 

1912 

1913 

1914 

1913 

1912 

1913 

1912 

1914 
1917 

Followed by Cyanide 

Followed by Cyanide. 

Followed by Cyanide. 

Followed by Cyanide. 

Followed by Cyanide. 

No Amalgamation 


. 



2.50 

92 

1 05 

82 


4- These are partial costs, as extraction is completed in Cyanide operation 
following. 
























































































CONSULTING ENGINEERS 


35 


Cost of Mill Operations 


Gold Mills All Slime Cyaniding 


Average Conditions 


Tons 

2 4-Hrs. 

1 

Location 

Value 
Extr 
per ton 

xtrn 

% 

Treatment Details 

Cost 

Per 

Ton 

% 

-200 

Date 

Remarks 

85 

California 

114.00 

95 

Cr St. Peb. Cy. 

$1.73 


1912 


115 

Montana 

11.55 


Cr. Peb. Cy. 

2.00 


1918 

Sand Leaching. 

150 

200 

Colorado 

Korea 

6.50 

92 

Milling 

Cr. St. Peb. Cy. 

1.90 

1.01 


1912 

1914 

200 

Cent. Am. 

7.00 


Milling 

1.50 


1910 


250 

Colorado 

26.00 

94 

Cr. St. Peb. Cone. Cy. 

1.80 


1908 


250 

New Zealand 



Cr. St. Peb. Cone. Cy. 

1 52 


1915 


300 

California 



Cr. St. Ama. Peb. Cone. Cy. 

0 79 


1913 


300 

California 

11.00 

97 

Cr. St. Cone. Peb. Cy. 

0.98 


1912 


350 

Canada 

20.50 

95 

Cr. St. Peb. Cone. Cy. 

1.49 


1913 


400 

Colorado 

2.25 

75 

Cr. Roll. Peb. Cone. Cy. 

1.31 


1913 


400 

California 

9.35 


Cr. St. Amal. Peb. Cone. Cy. 

1.07 


1917 


500 

Colorado 

6.50 

93 

Cr. St. Amal. Peb. Cone. Cy. 

1.38 

74 

1913 


500 

Transvaal 

6.25 

. 

Cr. St. Peb. Cy. 

0.96 

60 

1913 


500 

Transvaal 

11.25 


Cr. St. Peb. Cy. 

1.09 

60 

1913 


600 

Canada 

13.00 


Cr. St. Peb. Cy. 

1.24 


1914 


700 

India 

17.00 

85 

Cr. St. Peb. Cy. 

0.86 


1907 


875 

Transvaal 

4.70 


Cr. St. Peb. Cy. 

0.87 

60 

1913 

i. .. . j 

1000 

Transvaal 

4.50 


Cr. St. Peb. Cy. 

0.91 

60 

1913 

> * ' 

1100 

Transvaal 


93 

Cr. St. Peb. Cy. 

0.82 

62 

1913 

Sands Treated Separately. 

1350 

Transvaal 

6.20 


Cr. St. Peb. Cy. 

0.85 

60 

1913 

- - - 

1400 

Transvaal 

10.00 


Cr. St. Amal. Peb. Cy. 

0.84 


1918 


1500 

Transvaal 


93 

Cr. St. Peb. Cy. 

0.69 

60 

1913 


2000 

Transvaal 

4.00 


Cr. St. Peb. Cy. 

0.85 

60 

1913 


, 2000 

Transvaal 

9.70 


Cr. St. Peb. Cy. 

1.22 


1919 

Same 

2500 

Transvaal 

8.70 


Cr. St. Peb. Cy. 

1.02 


1917 

Plant 

4000).So. Da ota 

3-4 


Cr. St. Amal. Peb. Cv. 

0 79 

30 

1914 

Sands Treated Separately. 


Desert Conditions 


Tons 

24-Hrs. 

Location 

Value 
Extr 
per ton 

xtrn 

% 

Treatment Details 

Cost 

Per 

Ton 

o 

nO° 

1 

Date 

Remarks 

70 

California 

$5.70 

95 

Cr. St. Am. Cy. 

$4.02 


1912 

30 tonB stamped, bal. tailings 

100 

So. Africa 

11.00 

.93 

Cr. St. Ch. Pan. Cy. 

2.05 


12-13 


150 

Arizona 

20.00 

95 

Cr. St. Peb. Cy. 

2.50 

70 

1913 

Same 

200 

Arizona 

7.60 

• 

Cr. St. Peb. Cy. 

2 04 


1917 

Property 

250 

Arizona 

22.00 

96 

Cr. Ball. Peb. Cy. 

1.79 

82 

17-18 


270 

Nevada 

6.50 

80 

Cr‘ Roll. Ball. Peb. Cy. 

1.59 

70 

1914 


400 

Mexico 

7.25 

..... 

Cr. St. Peb. Cy. 

1.61 

.... 

1912 


500 

Nevada 

5.00 


Cr. St. Peb. Cy. 

1.12 


1912 


1000 

Mexico 

5.75 

85 

Cr. St. Peb. Cy. 

111 


1912 


1000 

Nevada 

13.70 

92 

Cr. St. Ch. Peb. Cone. Cy. 

1.97 

75 

1913 

$2.20 cost in 1908 on 

900 

Nevada 

12 50 

92 

Cr. St. Ch. Peb. Cone. Cv. 

1.61 

75 

1914 

$10 Xt-n 

























































36 


THE GENERAL ENGINEERING COMPANY 


Partial Milling Costs 

CRUSHING 

This general term applies to all milling processes which aim 
to reduce the sizes of the pieces of ore. For cost purposes it has 
been found practical to make four rough divisions of crushing; 

BREAKING (preliminary crushing, coarse crushing) is the 
first operation and is done in Gyratory or Jaw Breakers or Crush¬ 
ers. Costs depend upon the character of the ore, the cost of pow¬ 
er, and the load factor of the crushing unit, more than upon the 
relative capacity of the plant, according to most reported costs. 
Size of product: all through 1to 3”. 

Cost of Breaking, per ton of mill feed_$0.07 to 0.13 

SECONDARY CRUSHING (intermediate crushing, fine 
crushing, stamping) follows breaking, and aims to give a product 
about all of which passes 4-mesh; it is performed with rolls, disc 
crushers, and stamps. 

Cost of Secondary Crushing, per ton of mill feed_$0.10 to 0.20 

GRINDING (comminuting, pulverizing, primary grinding) 
gives a product of which 15% to 50% passes through a 200-mesh 
screen; BALL MILLS, Chileans, and pans are the commonly used 
machines. 

Cost of Grinding, per ton of mill feed_$0.10 to 0.20 

SLIMING (regrinding, fine grinding, secondary grinding, tube¬ 
milling) reduces a feed, all of which passes a 10-mesh to 20-mesh 
screen, and gives a product of which 50% to90% passes through 
a 200-mesh screen. This is generally done in tube mills using peb¬ 
bles or small balls; it is also partially done in ball and rod mills. 


Cost of Sliming, per ton of mill feed_$0.15 to 0.50 

COST OF ALL CRUSHING TO SLIME, for each percent- 
minus-200-mesh, per ton of run-of-mine ore,_ y to \ l / 2 cents 


Stamps, Chileans and Ball Mills are occasionally used for the 
combined operations of Secondary Crushing and Grinding, with a 
cost about equal to the sum of the two partial costs given above. 

CONCENTRATING 

By Vanners and Tables in Gold Stamp Mills, following Amalgama¬ 
tion, 

Cost per ton of mill feed-$ 0.04 to 0.15 

By Jigs, Tables and Vanners on Lead and Copper Ores, 

Cost per ton of mill feed_ 0.20 to 0.40 

By Tables after Flotation, 

Cost per ton of mill feed- 0.05 to 0.10 

By Flotation, 

Cost per ton of mill feed 


0.06 to 0.30 











CONSULTING ENGINEERS 37 


CYANIDING (not including crushing) 

per ton milled 

SAND LEACHING, previous to 1912 (now ob¬ 
solete) -- 0.15 to 1.25 

ALL SLIMING, Silver_ 1.00 to 2.00 

ALL SLIMING, Gold_ 0.50 to 1.00 

ALL SLIMING, Gold, South Africa only_ 0.30 to 0.60 

Partial Costs: (Excluding South African figures) 

Chemicals, Gold_ 0.25 to 0.60 

Chemicals, Silver_ 0.75 to 1.25 

Classifying _ 0.02 to 0.05 

Agitation_ 0.05 to 0.10 

Filtering, both cyanide and flotation slimes,_ 0.05 to 0.15 

Clarifying, Precipitating and Refining_ 0.15 to 0.50 

(higher costs are for silver ores) 

per ton so treated 

Roasting ores and concentrates_ 0.65 to 1.25 

COPPER LEACHING 

per ton milled 

Tailings, with Sulphuric acid, precipitated on 

scrap, 1914 2,000 tons daily capacity_est. 0.70 

Oxidized Ores, with Sulphuric Acid, 1918, 1,200 

tons daily_est. 1.06 

DREDGING 

River bottom carrying an average of 8.66 cents per yard, 1919, 
5,000 yards per day, cost per yard-6.41 cents 

MISCELLANEOUS 

per ton milled 

Water _ 0.01 to 0.25 

General Expense, including Superintendence, Assaying, etc. 

Small plant_about 0.75 

Large plant, several thousand tons-about 0.10 



















38 


THE GENERAL ENGINEERING COMPANY 


Cost of Power 

STEAM POWER 


Costs per H. P. 


per 24 hrs. 

Non-Condensing Engines, coal at $7.00_$ 0.20 to 0.22 

Condensing Engines _ 0.17 to 0.19 

Compound Condensing Engines_ 0.14 to 0.17 


For each variation of $1.00 per ton in cost of coal, costs per H. P. 
should be varied: \ l / 2 cents for Non-Condensing Engines, 1% 
cents for Condensing Engines, 1 cent for Compound Condensing 
Engines. 

A rough general figure for power costs in mining camps is 
$0.30 per H. P. per 24 hours. 

See also “Steam Plants" (page 45) giving fuel consumption 
for different operating conditions, from which costs may be cal¬ 
culated. 


ELECTRIC POWER 

Charges for electric power are usually based upon a variety of 
factors, in which the total power consumed and maximum demand 
have most influence in determining the rate. 

The following rate comparison is based upon reported costs of 


power in milling plants: 




Per 

Per 

Per 


H.P. year 

H.P. month 

K.W. 

hour 

Conditions 

$150.00 

$12.50 

2.0 cents 

Desert and unfavorable 

120.00 

10.00 

1.6 

>> 

>> )> V 

90.00 

7.50 

1.2 



75.00 

6.25 

1.0 


Average 

60.00 

5.00 

0.8 

>> 


45.00 

3.75 

0.6 


Favorable 

30.00 

2.50 

0.4 

>5 

>> 


Above Agues are for 360 24-hour days per year, and an aver¬ 
age motor efficiency of 85 to 88 per cent. 


The diagram following gives monthly power costs for vari¬ 
ous powers, for various “load factorsthe load factor being the 
ratio of average load to maximum demand. In this schedule a 
discount of 10% is allowed when load factor is maintained at 50% 
or higher. Load factors based upon maximum demand vary from 
50% to 95%, with an average around 70% ; based upon connected 
load (ratio average power to total motor H.P.) this factor would 
vary between 40% and 65%. 







Dollars per Month. jo 2*-** 


CONSULTING ENGINEERS 


39 


Horse- power 



C051 of ELECTRIC POWER 

3 PHA5P SERVICE 2300 15000 Volts QlOOO NORMAL.) 
actual power based upon: 3 % transformer loss -4% vn» loss, and 

B6% MOTOR EFFICIENCY ONE MOTOR HP MONTH R.EOVIHES 6’0 KW HRS 

MAXIMUM DEMANO: th t HIGHEST average J MIN LOA0 AS METCRCO 

LOAD FACTO* . ratio of average load to max demand 



Drafting Room 

The General Engineering Company 
Salt Lake City, Utah 














































































































































































































































































































40 


THE GENERAL ENGINEERING COMPANY 


CONSULTING ENGINEERS 


41 



Pneumatic Flotation Plant 

Utah Consolidated Mining- Company, Tooele, Utah. 
Desig-ned and built by the General Engineering Company 

f 











42 


THE GENERAL ENGINEERING COMPANY 


Cost of Erection 

MILLING PLANTS 

Cost per ton 
capacity 
per 24 hrs. 

Coarse Concentration, no Flotation-$ 300 to $ 450 

Gravity Concentration and Flotation- 800 to 1,200 

All Flotation_ 600 to 800 

Cyanide, All-Slime, Stamps or Ball Mills, 

Pebble Mills, Filtering or Counter-Current,— 1,000 to 1,400 

Stamps, with Manners_ 475 to 550 


An empirical figure for the erection and installation of ore 
mills and similar reduction plants is: $1.25 to $1.50 for each $1.00 
cost of machinery, f. o. b. factory. 

Under ordinary conditions, as found in mining camps, the cost 
of Mill Buildings may be arrived at as follows: 

Wooden Buildings_3 to 6 cents per cubic foot of volume 

Steel Buildings_7 to 10 cents per cubic foot of volume 

Erecting Mill and Smelter Buildings, 

Wood, $30.00 to $40.00 per 1,000 feet B. M. 

Steel, 0.75 to 1.5 cents per pound of steel. 

Erection of Sectionalized machinery, two to three times that 
for standard equipment. 

POWER 

HORSE-POWER lor DIFFERENT TYPES of MILLS 

H.P. per ton 


milled in 
24 hours. 

Crushing only, product to contain 60-80% minus- 

200 - mesh- 0.80 to 2.50 

Coarse Gravity Concentration, 10-20 mesh_ 0.50 to 0.80 

Stamp Mills with Vanners, 20-40 mesh_ 0.75 to 1.00 

Gravity Concentration, Tables and Vanners, 30-100 

mesh - 1.50 to 1.75 

Concentration, all Flotation_ 1.25 to 4.00 

Cyanide Mills, dry rolls, to 20 mesh_ 0.50 to 0.80 

Cyanide Mills, wet stamping to 80 mesh_ 2.00 to 3.50 

Magnetic Separator Mills- 0.25 to 0.50 

Combination Stamp Mills, 16-30 mesh_ 1.50 to 1.75 

COSTS OF POWER, see under Costs 



















CONSULTING ENGINEERS 


43 


POWER UNITS AND RELATIONS 

One HORSE-POWER equals: 

550 foot-pounds per second 

33,000 foot-pounds per minute 

1,980,000 foot-pounds per hour 

2,545 B. T. U. (British Thermal Units) per hour 

746 Watts, or 0.746 Kilowatts 

4,562 Kilogram-Meters per minute 

0.986 Metric Horse-Power 

One Foot-Pound is the work required to raise one pound one 
foot, or overcome the resistance of one pound for one foot. 

One B. T. U. (equal to 778 foot-pounds) is the heat required to 
raise one pound of water one degree F. (from 62° to 63°). 

ELECTRICITY 

VOLT is the unit of electrical pressure, electromotive force, 
or difference of potential. Symbol-E. 

OHM is the unit of electrical resistance. Symbol-R. 

AMPERE is the unit of electrical current, or rate of flow of 
electricity. Symbol-I. 

Ohm's Law expresses the relations between the above: 

E F 

I = — ;R = — ; E = IR 
R I 

WATT is the unit of electrical power, that delivered by one 
ampere at one volt pressure. 746 watts equal one horsepower. One 
thousand watts equal one Kilowatt. 

With Direct Current, and single phase alternating at 100% 
power factor. 

Watts, W = El = PR 

With Alternating Current, power.factor (PF) and phases affect 
power. 

POWER FACTOR (symbol PF) is the ratio of actual watts 
to the product of current and voltage from switchboard readings. 

Watts, Single phase, W = El times PF. 

Watts, Three phase, W = 1.732 times above. 

Current, single phase, I = W divided by product of E and PF. 

Current, three phase, I = 0.578 times above. 

Three phase Generator Current = 0.578 W divided by product 
of E and PF. 

Three phase Motor Current = 0.578 HP times 746 divided by 
product of E and PF. 

KILOWATT-HOURS-per-TON equals 21 times total Horse¬ 
power divided by tons-per-24-hours, when motor efficiency is about 
85%. 




THE GENERAL ENGINEERING COMPANY 


44 


Electrical Power Transmission 

Copper Wire Table 

Dimensions, Weights, Resistances, Carrying Capacities 


No. 

Diam. 

Inches 

Area 

Circ. Mils 

Weight 

Lbs. 

Per 

1000 Ft, 

Resistance 

Ohms 

Per 

1000 Ft. 

Carrying 

Amperes 

Rubber 

Insulation 

Capacity 

Amperes 

Other 

Insualtion 

0000 

.460 

211 600 

639 

.049 

225 

325 

000 

.410 

167 800 

507 

.062 

175 

275 

00 

.365 

133 080 

402 

.078 

150 

225 

0 

.325 

105 540 

319 

.098 

125 

200 

1 

.289 

83 690 

253 

.124 

100 

150 

2 

.258 

66 370 

201 

.156 

90 

125 

3 

.229 

52 630 

159 

.197 

80 

100 

4 

.204 

41 740 

126 

.249 

70 

90 

5 

.182 

33 100 

100 

.314 

55 

80 

6 

.162 

26 250 

79.3 

.395 

50 

70 

8 

.128 

16 510 

49.9 

.629 

35 

50 

10 

.102 

10 380 

31.4 

1.00 

25 

30 

12 

.081 

6 530 

19.7 

1.59 

20 

25 

14 

.064 

4 110 

12.4 

2.53 

15 

20 

16 

.051 

2 580 

7.8 

4.02 

6 

10 

18 

.040 

1 620 

4.9 

6.39 

3 

5 


Carrying Capacity, according to National Board of Fire Under¬ 
writers, is independent of Voltage Drop. 

To determine size of conductor: 

21.6 DI 

Circ. Mils --•, 

E 

Where 

D = Length of Transmission (one way) 

I = Current in Amperes. 

E = Total Volt Drop in wires 

The above applies only to a Direct Current, or Single Phase 
Alternating with 100% Power Factor. Circular mills vary inversely 
as power factor. 

Volt Drop in wires vary from 2% to 10% of the initial line vol¬ 
tage, and is a direct proportional loss of power. 

For THREE PHASE Current, (given equal voltage, drop, and 
power), and at about 86% power factor, the total copper required is 
75%' of that required for direct current: in other words there will be 
three wires each of one-half the area of those required for the equal 
power direct current transmission. When value of current is ob- 
tnined from motor manufacturer (or on name plate) it may be ap¬ 
plied in the above formula without further allowance. 


(For Induction Motor Current, see page 46). 




















CONSULTING ENGINEERS 


45 


Steam Plants 


Coal and Water Consumption and Boiler Capacities for Various 
Types and Sizes of Steam Engines 


ENGINES 

TYPE 

Size 

H. P. 

1 

Gals. 
Per 
Min. 
Full 
Load 
D( liv. 

VATER 

Pounds 

Per 

I. H. P. 

j FOR 

Boil°r 
H. P. 
Includ 
Aux i! 

DELIVERED H. P. 

| COAL—TONS P 
At Full Load—125-! 
10.000 BTU Per Lb. 
For Following Boiler 
40 | 50 1 60 
Hnriz. Tubular 

OF R; 

rr 24 H 
50 lbs. 
Coal 
Efficie 
70 

1 . 

rine 
ater T 

1TING 

ours 

Press. 

18 Us< d 
acies 

80 

ube 

Full 

Load 

Half 

I oad 


Sco 

ch Ma 
W 

Throttling 

50 

5 

39 

41 

80 

8.2 

6.3 




Plain Slide Valve 

100 

9 

36 

39 

145 

15 1 

11.7 




Non-Condensing 

150 

12 

34 

37 

205 

21 4 

16.5 




Automatic 

100 

7 

29 

30 $ 

115 

13 3 

10.4 




PI. Slide or Piston V. 

200 

12 

27$ 

29 

220 

25 0 

19.5 

16.4 



Non-Condensing 

300 

17$ 

26$ 

28 

305 

35 0 

29.9 

22.9 



Automatic 

150 

8$ 

23 

28 

140 

15 7 

12.2 

10 4 



Tandem-Compound 

300 

15 

22 

26^ 

255 

28 7 

22.5 

19 0 

16 5 


N on-Condensing 

450 

21$ 

21$ 

26 

370 


32.9 

27.9 

24.3 

21 3 

Corliss 

200 

10 

22 

25 

175 


15.6 

13.1 

11.4 


Simple 

400 

19 

21$ 

24$ 

330 


29.1 

24.9 

21.5 

18.9 

Non-Condensing 

600 

27 

21 

24 

485 


42.5 

36.3 

31.5 

27.6 

Corliss 

300 

13 

19i 

26 $ 

225 



16.9 

14.6 

12.9 

Compound 

600 

25 

19 

26 

435 



32.8 

28.5 

25.0 

Non-Condensing 

900 

37 

18$ 

25$ 

610 



46.0 

40.0 

35.0 

Corliss 

500 

17 

14£ 

16 

280 



20.9 

18.3 

15.9 

Compound 

1000 

31 

13£ 

151 

505 



38.0 

33.0 

29.0 

Condensing 

1500 

44 I 

131 

15 

730 



55.0 

48.0 

42.0 


Auxiliaries and steam losses are included in boiler H. P. and 
coal consumption on following basis: Up to 200 H. P., 20% ; 300-600 
H. P., 15% ; 900 to 1,500 H. P., 10%. 


Mechanical efficiency of all engines figured at 91%. 

10000 BTU for coal as used is a lower value to cover coals with 
high ash ; for other values, coal will vary inversely. 12,000 BTU is 
perhaps nearer normal. 

Boiler H. P. calculated for feed water at 60 degrees F., 30# 
steam per hour per H. P. If feed is heated by exhaust, reduce rating 
and coal consumption 1% for every 12 degrees feed temperature is 
higher than 60 degrees F. 






















































46 


THE GENERAL ENGINEERING COMPANY 


Induction Motors 

FULL LOAD CURRENT—RUNNING 

Approximate Amperes per Terminal. For determining- size of 
wires, capacity of fuse, and setting of circuit breakers. 

For single phase motors, multiply the current per terminal for 
a two phase motor by two. 


H. P. 

110 Volts 

220 Volts 

440 Volts 

550 V. 

1100 V. 

2200 V. 

Motor 

2 Ph. 

3 Ph. 

2 Ph. 

3 Ph. 

2 Ph. 

3 Ph. 

3 Ph. 

3 Ph. 

3 Ph. 

, .5 

3.3 

3.7 

1.7 

1.8 

.9 

1.0 




1 

6 

6.5 

3. 

_3.2 

1.5 

1.6 




2 

10.5 

12 

5. 

6. 

2.6 

3. 

2.5 



3 

15 

17 

7.5 

9. 

3.8 

4.5 

3.5 



5 

27 

30 

13. 

15. 

6.5 

7.5 

6. 



7.5 



20. 

22. 

10. 

11. 

9. 



10 



25. 

29. 

12.5 

14. 

11. 



15 



35. 

41. 

18. 

20. 

16. 



20 



48. 

55. 

24. 

27. 

22. 



25 



54. 

62. 

27. 

31., 

25. 



30 



70. 

81. 

35. 

40. 

32. 

16 

8 

40 



95. 

109. 

47. 

54. 

44. 

21 

11 

50 



110. 

127. 

55. 

64. 

52. 

27 

18 

75 



165. 

192. 

83. 

96. 

77. 

39 

20 

100 



215. 

248. 

108. 

124. 

100. 

50 

25 

150 



320. 

366. 

160. 

183. 

147. 

80 

40 

200 


1 

410. 

475. 

205. 

237. 

192. 

98 

49 

250 



510. 

590. 

250. 

295. 

237. 

125 

62 

300 



600. 

700. 

300. 

350. 

285. 

150 

74 


From catalog, Westinghouse E. & M. Co. 


Water and Pulp 

Liquid or Fluid Measure 

4 gills = 1 pint, .pt. 

2 pints = 1 quart, qt. 

4 quarts = 1 gallon, gal. 

31^4 gals, is frequently given as the equivalent of a barrel, 
but there is no standard barrel in the U. S., the capacity varying 
between this value and something over 50 gals. 

1 cubic foot of water = .62.425 pounds = 28.3153 kilograms 
(kilos) = 7.48 gals. 

1 cubic inch of water = 0.036125 pounds = 252.88 grains = 
16.386 grams. 

1 ton of water = 32.038 cubic feet = 239.665 gallons. 

1 pound of water = 0.016019 cubic foot = 0.47933 quart = 
27.681 cubic inches = 0.45359 liter. 

1 U. S. gallon of water = 8.3448 pounds = 3785.3 grams. 

1 cubic meter of water = 2204.6 pounds. 

1 kilogram of water = 1 liter of water = 2.2046 pounds = 
0.035317 cubic foot = 61.027 cubic inches = 1.0567 quarts. 

1 cubic centimeter of water = 1 gram = 0.001 kilogram = 
15.432 grains. 









































CONSULTING ENGINEERS 


47 


Multipliers 

Cu. ft. per sec. X 449 = U. S. gals, per min. 

U. S. gals, per min. X 3.85 = Cu. inches per sec. 

U. S. gals, per min. X 6 = Tons of water per day. 

U. S. gals, per min. X 300 = Pounds of water per hour. 
Note—All the above figures are for water at specific gravity of 
1 . 000 . 


Specific Gravity 

Definition: The Specific Gravity of a solid or liquid is the 
ratio of the weight (mass) of the body to the weight (mass) of an 
equal volume of water under standard conditions. Density, which 
is frequently used for specific gravity is the mass (weight) per unit 
volume, and is the same if grams-per-cubic-centimeter is calcu¬ 
lated, but of course different if pounds-per-cubic-foot is used. 

Pure water at a temperature of 4° C or 39° F is at its maximum 
density and has a specific gravity of 1.000. 

Sea water averages 1.028 specific gravity; it contains about 
3.44% solids, of which about 2.5% of the total is sodium chloride. 

The waters of Great Salt Lake and of the Dead Sea have a 
specific gravity of 1.17 and contain about 22.4% solids. 


Water Requirements of Mills 



tons 

water 

Gals. 

p. m. 

Coarse Gravity Concentration, 

per 

ton 

ore 

per 

24 hr-ton 

Crushers, rolls, jigs, tables 

Gravity Concentration, 

Crushers, ball and pebble mills, 

15 

to 

20 

2.5 

to 

3.5 

tables, vanners 

7 

to 

10 

1.2 

to 

1.7 

Stamp Mills, with vanners 4 

Gravity and Flotation Concentration, 
Crushers, ball and pebble mills, 

to 

6 

0.7 

to 

1.0 

tables and flotation 

All Flotation Concentration, 
Crushers, ball and pebble mills, and 

5 

to 

7 

0.8 

to 

1.2 

flotation 

Cyanide Mills, shoveling tailing 

3 

to 

6 

0.5 

to 

1.0 

and filter-pressing 

0.2 

to 

0.35 

0.03 

to 

0.06 

Cyanide Mills, sluicing tailing- 

1.3 

to 

1.9 

0.2 

to 

0.35 


Above quantities do not include water for boilers nor return 
circuit water. With settling tanks or ponds, from 50% to 60% of 
the original water (except in case of mills shoveling tailing) is 
available for use on return to the mill circuit With automatic 
discharge tanks for sand and decantation tanks for slime, from 
75% to 80% of the original water may be recovered and used 
again in the mill circuit. 

For water requirements in individual machines, see particular 
machine under Mill Machinery. 











48 


THE GENERAL ENGINEERING COMPANY 


Pulp Calculations 

Let W = weight of a given volume of water (1 gram = 1 c.c.) 
Ws = weight of an equal volume of dry solids. 

Wp = weight of an equal volume of pulp, or by wetting sol¬ 
ids to make water level equal. 


Gs = specific gravity of solids = 


Ws 


Gp = specific gravity of pulp 
Gp- 1 


W- (Wp- Ws) 
Wp 


w 


Ws = 


GsW 


Gs - 1 

S = percent of solids in pulp = 100 

Gp 


Gp -1 


X 


Gs 


Weight per cubic foot 
Cubic Feet per ton = 


Gs - 1 Gp 

tons = 62.425 Gp pounds. 


32.038 

Gp 


Cubic Feet pulp per ton dry solids 


32.038 (Gs - 1) 
(Gp - 1) Gs 

Gs-Gp 


Percent water in pulp = 100 - S = 100- ^ 

Tons of dry solids per foot depth for round tanks of diameter 

n , r .. _ D 2 (Gp - l)Gs 
D (in feet) 40.8 (Gs-1) 

See also Table of “Pulp and Sludge Density Relations.” 


Water Piping in Mills 


2/ U. S. gals, p. Min. X 0-41 
Nominal Diameter of Pipe, D = V velocity in ft. p. sec 

GALLONS per Minute 


Pipe diam. D 

1 

2 

3 

4 

1 

1-1 

1-1 

2 

2-1 

3 

4 

5 

at 6 ft. p. s. 
maximum 

3-1 

8.2 

14.6 

23 

33 

58 

91 

130 

233 

365 

at 4 ft. p. s. 
normal 

2-1 

5.5 

9.8 

15 

22 

39 

61 

87 

156 

245 


















































CONSULTING ENGINEERS 


49 


Pulp and Sludge Density Relations" 


Specific Gravity of Pulp and Volume of One Ton in Cubic 
Feet, for Slimes Containing Solids of Dif¬ 


ferent Specific Gravities. 


Per 

Cent 

Solids. 

Ratio of 
Solids to 
Solution. 

2.50 

'2.70 

2.90 

3.10 

3. 

30 




S. G. 

Vol. 

S. G. 

Vol. 

S. G. 

Vol. 

S. G. 

Vol. 

S. G. 

Vol. 

5 

1 

19.000 

1.031 

31 03 

1 032 

30.99 

1.034 

30 95 

1.035 

30.92 

1.036 

30.89 

6 

1 

15.667 

1.037 

30.85 

1.039 

30.79 

1.041 

30 74 

1.042 

30.70 

1.043 

30.66 

7 

1 

13.286 

1.044 

30.66 

1.046 

30.59 

1.048 

30.53 

1.049 

30.48 

1.051 

30.43 

8 

1 

11.500 

1.050 

30.46 

1 053 

30.39 

1 055 

30 32 

1.057 

30.27 

1.059 

30.21 

9 

1 

10.111 

1.057 

30.27 

1.060 

30.19 

1.063 

30.11 

1.065 

30.05 

1.067 

29.99 

10 

1 

9.000 

1.064 

30.03 

1 067 

29.99 

1 070 

29.90 

1.072 

29.83 

1 075 

29.77 

11 

1 

8.091 

1.071 

29.88 

1 074 

29.79 

1.078 

29.69 

1.080 

29.61 

1.083 

29.54 

12 

1 

7.333 

1.078 

29.70 

1 082 

29.59 

1.085 

29.48 

1.088 

29.40 

1.091 

29.32 

13 

1 

6.692 

1 085 

29.50 

1 039 

29.39 

1 093 

29.27 

1.096 

29.18 

1.099 

29.10 

14 

1 

6.144 

1.092 

29.31 

1.097 

29.19 

1.101 

29.06 

1.105 

28.96 

1.108 

28.88 

15 

1 

5.667 

1.099 

29.18 

1.104 

28.99 

1.109 

28.85 

1 113 

28.74 

1.117 

28.66 

16 

1 

5.250 

1.103 

28.93 

1.112 

28.78 

1.117 

28.65 

1.122 

28.53 

1 125 

28.43 

17 

1 

4.882 

1114 

28.74 

1.119 

28.58 

1.125 

28.44 

1 130 

28.31 

1.134 

28.21 

18 

1 

4.556 

1.121 

28.54 

1.128 

28.38 

1.134 

28.23 

1.139 

28.10 

1 143 

27.99 

19 

1 

4.263 

1 129 

28.35 

1.136 

28.18 

1.142 

28 02 

1.148 

27.88 

1.153 

27.76 

20 

1 

4.000 

1.136 

28.17 

1.144 

27.98 

1.151 

27.81 

1 157 

27.66 

1.162 

27.54 

21 

1 

3.762 

1.144 

27.97 

1.152 

27.77 

1.159 

27.60 

1.166 

27.44 

1.171 

27.32 

22 

1 

3.545 

1.152 

27.78 

1.161 

27.57 

1.168 

27.39 

1.175 

27.23 

1.181 

27.09 

23 

1 

3 348 

1.160 

27.58 

1.169 

27.37 

1.177 

27.18 

1.184 

27.01 

1.191 

26.87 

24 

1 

3.167 

1.168 

27.39 

1.178 

27.17 

1.186 

26.97 

1.194 

26.79 

1.201 

26.65 

25 

1 

3.000 

1.176 

27.21 

1.187 

26.97 

1.195 

26.76 

1.204 

26.58 

1.211 

26.42 

26 

1 

2.846 

1.185 

27.01 

1.195 

26.77 

1.205 

26.55 

1.214 

26.37 

1.222 

26.20 

27 

1 

2.704 

1.193 

26.82 

1.205 

26.56 

1.215 

26.34 

1 .224 

26.15 

1.232 

25.98 

28 

1 

2.571 

1.202 

26.62 

1.214 

26.36 

1.224 

26 13 

1.234 

25.93 

1.242 

25.75 

29 

1 

2.448 

1.211 

26.43 

1.223 

26 16 

1.234 

25.92 

1.244 

25.71 

1.253 

25.53 

30 

1 

2.333 

1.220 

26.24 

1.233 

25.95 

1.244 

25.71 

1.255 

25.50 

1.264 

25.31 

31 

1 

2.226 

1.229 

26.05 

1.242 

25.75' 

1.255 

25.50 

1.266 

25.28 

1.275 

25.08 

32 

1 

2.125 

1.233 

25.86 

1.2^2 

25.55 

1.265 

25.29 

1.277 

25.06 

1.287 

24.86 

33 

1 

2.030 

1.247 

25.66 

1.262 

25.35 

1 .276 

25 08 

1.288 

24.85 

1.299 

24.64 

34 

1 

1.940 

1.256 

25.47 

1.272 

25.15 

1.287 

24 87 

1.299 

24.63 

1.311 

24.41 

35 

1 

1.857 

1.266 

25.28 

1.283 

24.95 

1.298 

24.66 

1.310 

24.41 

1.323 

24.19 

36 

1 

1.778 

1.276 

25.09 

1.293 

24 75 

1.309 

24 45 

1.322 

24.19 

1.335 

23.97 

37 

1 

1.703 

1.285 

24.90 

1.304 

24.55 

1 320 

24.24 

1 334 

23.98 

1.347 

23.75 

38 

1 

1.632 

1.295 

24.70 

1.314 

24 35 

1.332 

24 03 

1.346 

23.76 

1.360 

23.52 

39 

1 

1.564 

1.303 

24.51 

1 326 

24 14 

1.343 

23.82 

1.358 

23.55 

1.373 

23.30 

40 

1 

1.500 

1.316 

24.32 

1.336 

23.95 

1 355 

23.61 

1.371 

23.33 

1.387 

23.08 

41 

1 

1.439 

1.326 

24.13 

1.348 

23.74 

1.367 

23.40 

1.384 

23.11 

1.400 

22.85 

42 

1 

1.331 

1.337 

23.94 

1 .359 

23.55 

1.380 

23.19 

1.396 

22.89 

1.414 

22.63 

43 

1 

1 326 

1.348 

23.74 

1.371 

23.34 

1.392 

22 99 

1 411 

22.68 

1.428 

22.41 

41 

1 

1.273 

1.359 

23.55 

1.383 

23.15 

1.405 

22.78 

1 .425 

22.46 

1.442 

22.18 

45 

1 

1.222 

1.370 

23.36 

1.395 

22.94 

1.418 

22.57 

1.438 

22.24 

1.456 

21.96 

46 

1 

1 174 

1.381 

23.17 

1 .408 

22.73 

1.432 

22.36 

1.452 

22.02 

1.471 

21.74 

47 

1 

1.128 

1.393 

22.98 

1 .420 

22.54 

1.445 

22 15 

1.467 

21.81 

1.487 

21.51 

43 

1 

1 0^3 

1.404 

22.78 

1.433 

22.33 

1.458 

21.94 

1.483 

21.60 

1.503 

21.29 

49 

1 

1 041 

1.416 

22.59 

1.446 

22.13 

1.473 

21 73 

1.497 

21.38 

1.519 

21.07 

50 

1 

1 000 

1.429 

22.39 

1 .460 

21.92 

1.487 

21.52 

1.512 

21.16 

1.535 

20.85 

51 

1 

0 961 

1.441 

22.21 

1 473 

21.72 

1 f 02 

21.31 

1.528 

20.94 

1.551 

20.62 

52 

1 

0.923 

1.453 

22.02 

1 .'487 

21.52 

1.517 

21.10 

1.544 

20.73 

1.568 

20.40 

53 

1 

0 837 

1.466 

21.82 

1.501 

21.32 

1.532 

20.89 

1 .560 

20.51 

1.585 

20.18 

54 

1 

0.852 

1.479 

21.63 

1.515 

21.12 

1.548 

20 68 

1.577 

20.29 

1.603 

19.96 

55 

1 

0.809 

1 493 

21 44 

1.530 

20 92 

1.564 

20 47 

1.594 

20.08 

1.621 

19.73 

56 

1 

0 786 

1.505 

21.25 

1.545 

20.72 

1.580 

20.26 

1.611 

19.87 

1.640 

19.51 

57 

1 

0 754 

1.520 

21 05 

1.560 

20.51 

1.596 

20.05 

1.628 

19.65 

1.659 

19.29 

53 

1 

0 724 

1.534 

20.86 

1 .574 

20.31 

1.613 

19 81 

1.646 

19.43 

1.678 

19.06 

59 

1 

0.695 

1.548 

20.67 

1.591 

20.11 

1.629 

19.63 

1.665 

19.21 

1.697 

18.84 

60 

1 

0.667 

1.563 

20.48 

1 .607 

19.91 

1.645 

19.42 

1.684 

19.00 

1.718 

18.62 

61 

1 

0 639 

1.577 

20.29 

1.623 

19.71 

1.664 

19.21 

1.704 

18.78 

1.739 

18.39 

62 

1 

0.613 

1.592 

20.10 

1.641 

19.51 

1.683 

19.00 

1.724 

18.56 

1.761 

18.17 

63 

1 

0.587 

1.603 

19.90 

1.657 

i9.ro 

1.703 

18.79 

1.745 

18.34 

1.783 

17.95 

64 

1 

0.563 

1.623 

19.71 

1.675 

19.10 

1 723 

13.58 

1.765 

18.12 

1.805 

17.72 

65 

1 

0.538 

1.639 

19.52 

1 69 1 

18.90 

1.742 

18.37 

1.786 

17.91 

1.828 

17.50 

66 

1 

0.515 

1.66 

19.32 

1.711 

18.70 

1.76? 

18 16 

1.803 

17.69 

1 .852 

17.28 

67 

1 

0.493 

1.672 

19.14 

1.730 

18.70 

1.783 

19 93 

1.831 

17.47 

1.876 

17 06 

68 

1 

0.471 

1.689 

18.94 

1 749 

18.30 

1.803 

17.74 

1.854 

17.26 

1 901 

16.83 

69 

1 

0 449 

1.706 

18 75 

1.768 

18 10 

1.825 

17.53 

1 .878 

17.04 

1.927 

16.61 

70 

1 

0.490 

1.724 

18 5« 

1.786 

17 90 

1 8i7 

17 70 

1 902 

16.83 

1 953 

16.39 


*H. B. Lovilen, Metallurgical and Chemical Engineering, 


























































50 


THE GENERAL ENGINEERING COMPANY 


Circulating Feed 

To find total tonnage in a crushing element of a mill, when 
part of the load is returned from classifier or sizing screen, back 
to the beginning: 

100T 

Q =- 

100-P 


Where 


Example : 


T = Initial Tonnage per day, feed and discharge from 
element. 

P = % of oversize returned. 

Q = Total Tonnage per day through the element. 


100 X 100 

T == 100 tons, P = 75% Q = - 

100 - 75 


tons. 


Recovery and 



°f Concentration 


= 400 


Knowing the assay value of the Heads, Tails and Concentrates, 

C - T 100 C 100 C X (H - T) 

R =-, E =-, E= - 

H-T HR H X (C-T) 

Where 

H = heads assay, T = tailing assay, C = Concen¬ 
trates assay, 

R = ratio of concentration (tons into one,) E = re¬ 
covery in %. 

Example: 

Heads, 2.4% Pb; Tails, 0.95% Pb; 

Concentrates, 11.95% Pb. 

11.9-0.95 10.95 

R = - = - = 7.56, Ratio of 

2.4-0.95 1.45 Concentration. 

11.9X100 11.90 

E =-=- = 65.6%, Recoverv. 

2.4X7.56 18.15 




















CONSULTING ENGINEERS 


51 


Equivalents of Weights and Measures 

LENGTH 

1 mile = 5,280 feet = 1609.31 meters. 

1 foot = 12 inches = 0.30479 meter. 

1 inch = 25.3995 millimeters. 

1 kilometer = 1,000 meters = 0.62138 mile = 3281 feet. 

1 meter = 100 centimeters = 3.280899 feet = 39.370791 inches. 

1 centimeter = 10 millimeters = 0.393708 inch. 

1 millimeter = 0.039371 

SURFACE 

1 square yard = 9 square feet = 0.83610 square meter. 

1 square foot = 144 square inches = 9.2900 square decimeters = 929.00 
square centimeters. 

1 square inch = 6.4514 square centimeters. 

1 square meter = 100 square decimeters = 10764 square feet. 

1 square decimeter = 100 square centimeters = 0.10764 square foot = 
15.501 square inches. 

1 square centimeter = 100 square millimeters = 0.15501 square inch. 

1 square millimeter = 0.00155 square inch. 

VOLUME 

1 cubic yard = 27 cubic feet = 0.76451 cubic meter = 201.97 gallons. 

1 cubic foot = 1728 cubic inches = 0.28315 cubic meter = 7.4805 gallons 
= 28.3153 liters = 29.922 quarts. 

1 cubic inch = 0.017316 quart = 16.386 cubic centimeters. 

1 gallon = 4 quarts = 0.13368 cubic foot = ^231.0000 cubic inches = 
3.7852 liters. 

1 quart = 2 pints = 57.75 cubic inches = 0.94630 liters = 0946.30 cubic 
centimeters. 

1 cubic meter = 1,000 liters = 1.3080 cubic yards = 35.317 cubic feet= 
264.19 gallons- 

1 liter, or 1 cubic decimeter = 1,000 cubic centimeters == 0.035317 cubic 
foot = 61.027 cubic inches = 0.26419 gallons = 1.0567 quarts. 

1 cubic centimeter = 0.061027 cubic inch. 

*Taken from C. Herring. Table of Equivalents of Units of Measure¬ 
ment. 

WEIGHT 

1 ton = 2,000 pounds avoirdupois = 907.18 kilos. This is the ton used 
throughout this book unless otherwise specified. 

1 long ton = 2,240 pounds avoirdupois = 1016.05 kilos. 

1 metric ton = 1,000 kilos = 2204.62 pounds avoirdupois = 1.1023 tons 
= 0.98421 long ton. 

1 pound avoirdupois = 16 ounces avoirdupois = 0.45359 kilo = 7,000 
grains = 1.2153 pounds troy. 

1 pound troy = 5760 grains = 0.82286 pound avoirdupois = 12 ounces 
troy = 0.37324 kilo. 

1 ounce avoirdupois = 437.50 grains = 28.3495 grams = 0.91146 ounce 
troy. 

1 ounce troy = 480 grains = 20 pennyweights = 31.1035 grams = 
1.0971 ounces avoirdupois- The troy ounce and pound are used only 
for gold and silver and other precious metals. 

1 grain == 64.799 milligrrams. 

1 kilo or kilogram = 1000 grams = 2.2046 pounds avoirdupois. 

1 gram = 0.035274 ounce avoirdupois = 0.032151 ounce troy =15.43235 
grains = 1.000 milligrams. 

1 milligram = 0. 015432 grains. 





52 


THE GENERAL ENGINEERING COMPANY 


MISCELLANEOUS MULTIPLIERS 

Avoirdupois oz. per min. X 0-0450 = Tons per day. 

Troy oz. per min. X 0.04937 = Tons per day. 

Grams per mm. X 0.00159 =■ Tons per day. 

Tons per day X 630. = Grams per min. 

Tons per day X 1 -39 = Pounds Av. per min. 

Troy oz. per ton X 0.00343 = % per ton. 

% per ton X 292. = Troy oz. per ton. 

Avoirdupois ounces X 0.9114 == Troy oz. 

Troy ounces X 1-0971 = Avoirdupois oz. 

Grams X 0.0321 = Troy oz. 

Grams X 0.0353 = Avoirdupois oz. 

Millimeters X 0.04 = inches. 

Inches X 25. = millimeters. 

1 Gram per Metric ton = 62c in gold. 

1 Gram per Metric ton = 1.55 cents in silver (at 50c). 

1 Dwt. of gold = $1.00. 

1 Pound Avoirdupois = 453.60 grams. 

PRESSURE 

1 atmosphere at mean sea level = 760 millimeters or 29.922 inches 
of mercury column, = 10.333 meters or 33.001 feet of water 
column, = 14.696 pounds per square inch, = 1.0333 kilos per 
square centimeter. 

1 pound per square inch = 0 070310 kilo per square centimeter = 
2 041 inches of mercury = 2.31 ft. head of water. 

1 kilo per square centimeter = 14.223 pound per square inch. 


ALTITUDE EFFECTS 


Altitude 


Barometric Pressure 


Approx. 

Relative 

Above 

Mercury Col. 

Water Col. 

Pounds 

Boiling 

Volumetric 

Sea Level 

MM. 

Inches 

Feet 

Per Sq. In. 

Point-F 

Efficiency 

0 

762 

30.00 

34.0 

14.72 

212 

1.000 

1000 

7: 3 

23.85 

32.7 

14.17 

210 

0.965 

2000 

707 

27.82 

31.5 

13.64 

208 

0.93 

3000 

681 

23.82 

33.3 

13.13 

206 

0.S95 

4000 

657 

25.85 

29.2 

12.64 

204 

0.86 

5000 

631 

24.92 

28.1 

12.17 

292 

0.83 

6000 

613 

24.00 

27.0 

11.71 

231 

0.80 

7000 

5s7 

23.1 

23.0 

11.27 

199 

0.77 

8000 

562 

22 17 

25.0 

10.85 

197 

0.74 

9000 

540 

21.3 

24.1 

10.45 

195 

0.71 

10000 

517 

29.34 

2L2 

10.06 

193 

0.63 

11000 

503 

19.8 

22.4 

9.69 

191 

0.66 

12000 

485 

19.1 

21.6 

9.33 

190 

0.635 

13000 

464 

18.3 

29.8 

8.98 

188 

0.61 

14000 

447 

17.6 

29.0 

8.64 

186 

0 59 

15000 

432 

17.0 

19.3 

8.32 

184 

0.57 



























CONSULTING ENGINEERS 


53 


FALLING BODIES 


2h 

v = gt = 32.16 t = V2g h = 8.02 \/h =- 

t 


where 

v = velocity at the end of t seconds 
g == force (acceleration) of gravity, 
= 32.16 ft. p. sec. p. sec. 
h = height or space passed in t sec¬ 
onds. 

Idle following table gives the falls 
and maximum velocities (in feet per 
minute) for different periods of time 
from beginning of fall. Any other 
values within these limits may be 
found per interpolation, or by plott¬ 
ing three or four values nearest to 
that desired. 


Time 

Fall 

Velocity 

Max. 

Ft, P. M. 

Sec. 

Ft. 

In. 

0.05 


1 

2 

97 

0.10 


2 

193 

0.15 



290 

0.20 

.... 

7.7 

386 

0.25 


12. 

483 

0.3 

1 

5.3 

579 

0.4 

2 

6.7 

772 

0.5 

4 

0.2 

965 

0.6 

6 

1.2 

1158 

0.7 

7 

11.0 

1351 

0.8 

10 

3 

1544 

0.9 

13 

0 

1737 

1.0 

16 

1 

1930 

1.5 

36 

2 

2895 

2.0 

64 

4 

3860 

2.5 

100 

6 

4825 

3.0 

144 

9 

5790 


CENTRIFUGAL FORCE 

F = 1.227 W R n 2 = .000341 W R N 2 pounds where 
F = force or pull on the radius arm in pounds 
W = weight of the body in pounds 
N = revolutions per minute 
n = revolutions per second 




















54 


THE GENERAL ENGINEERING COMPANY 





Pneumatic Flotation Plant 

Designed and built by the General Engineering Company 


MILLING MACHINERY 

Owing to the diverse character of ores, the capacities, power 
consumption, water requirements, etc. of the various machines used 
in milling operations can only be given in very general figures. 

The information given in this section is for general estimating 
purposes, and while taken from reliable sources, it cannot be ex¬ 
pected to supplant the experience of engineers and operators in 
close touch with the development of the art of ore-treatment 

Crushing Machinery 

Some rocks offer as much as five times the resistance to crush¬ 
ing as others; this variation affects capacity, power and repairs. 

There is a constant development in crushing machinery, new 
machines replacing older types, larger sizes being developed,’ etc.; 
at the same time many of the very oldest of machines retain their 
position ; with possibly one or two exceptions, it is believed that 
the machines for which data is given represent those most in use 
at the time of this publication. 











CONSULTING ENGINEERS 


Blake Jaw Crushers 

(BREAKERS) 


Opening 

For 

Feed 

Inches 

CAPACITY 

Horse 

Power 

Min. P 

roduct 

Max. Product 

Size 

Inches 

Tons 

Per Hr. 

Size 

Inches 

Tons 

Per Hr. 

7x10 

a 

4 

U 

2 

5 

6-9 

9x15 

1 

6 

2\ 

12 

10-15 

10x20 

u 

10 

3 

20 

15-20 

12x24 

2 

20 

4 

35 

20-2S 

18x30 

9 1 

30 

5 

50 

35-50 

24x36 

4 

70 

6 

100 

50-60 


Gyratory Crushers 

(BREAKERS) 


Size 

No. 

Openings 

For 

Feed 

Inches 

CAPACITY 

Horse 

Power 

Min. 

Product 

Max. Product 

Size 

Inches 

Tons 

Per Hr. 

Size 

Inches 

Tons 

Per Hr. 

1 

5x18 

1 

4 

2 

8 

5-8 

2 

6x21 

1H 

6 

2i 

12 

7-12 

3 

7x22 

1 H 

10 

. 

20 

10-16 

4 

8x30 


15 

3 

40 

14-21 

5 

10x38 

if 

30 

3? 

70 

22-30 

6 

12x44 

2 

50 


90 

28-45 

n 

14x52 

2 h 

80 

4 

120 

50-75 

8 

18x68 


130 

4 

150 

70-110 

9 

21x76 

4 

250 

5 

300 

100-150 


Disc Crushers 


Size 

Diam. 

Discs 

Inches 

Opening 

For 

Feed 

Inches 

CAPACITY 

Horse 

Power 

To Run 

Min. T 

’roduct 

Max. Product 

Size 

Inches 

Tons 

Per Hr. 

Size 

Inches 

Tons 

Per Hr. 

18 

li 

% 

5-8 

1 

12-15 

12-18 

24 


1 

2 

12-15 

1J 

25-30 

18-25 

36 

Q 1 

a 2 

3 

4 

25-30 

2 

50-60 

30-40 

48 

6 

1 

45-60 

2£ 

100-120 

50-65 


Adapted from catalog, Chalmers & Williams, Inc. 
































































THE GENERAL ENGINEERING COMPANY 


56 


Crushing Rolls 


size 

Diam. x Face 
Inches 

Max. 

Feed 

Inches 

AT 50. K. T. M. 


Ai 100 H. P. M. 

Peripheral 

Speed 

Ft. P. M. 

Horse 

Power 

Capacity 

W 

Opening 

Pons 24Hr 

1" 

Opening 

Peripheral 
Speed 
Ft. P. M. 

Horse 

Power 

Capacity 

y*:\ 

Opening 

Tons 24H 

1" 

Opening 

9x9 


118 

\y 

13 


235 

2V 2 

26 


12x12 

Vi 

157 

2 

23 


315 

4 

47 


18x10 


235 

3 y> 

29 


470 

7 

58 


24x12 

1 

315 

6 

47 

190 

630 

12 

95 

380 

30x14 


390 

9 

68 

275 

780 

18 

137 

550 

36x14 

m 

470 

12 

82 

330 

940 

24 

165 

660 

42x16 

ih 

550 

15 

110 

440 

1100 

30 

220 

880 

48x16 

2 

630 

25 

125 

500 

1260 

50 

250 

1000 

54x20 

2H 

705 

40 

175 

700 

1410 

80 

350 

1400 

60x24 

2 H 

785 

65 

235 

940 

1570 

130 

470 

1880 

72x24 

3 

940 

100 

280 

1120 

1880 

200 

560 

2240 


Size represents commonly manufactured sizes. Power and 
capacity of other sizes will be proportional to both dimensions of 
nearest size given. 

Max. Feed is the size of rock the rolls should nip when close 
up. (15 deg. or 30 deg. “angle of nip”). While rolls will nip larger 
pieces (1-24 the diameter plus opening between rolls), the strength 
of the roll parts is such that it is generally inadvisable to crush 
pieces larger than designated. 

Speeds of rolls given in manufacturers tables are usually the 
maximum for which designed; the speeds here given cover the usu¬ 
al speeds; H. P. and capacity for other speeds being proportional. 
700 F. P. M. for coarse rock (max. feed), and 1000 F. P. M. for fine 
material, are common in larger plants, and for some very large rolls 
speeds nearly 2000 F. P. M. are used. 

Capacities are 10% of the theoretical; with proper feeding de¬ 
vices, capacities may be doubled and probably tripled. Capacities 
are proportional to opening; tabulated values are for material 
weighing 100# per cubic foot. 

Horse powers are for the capacities given, and indicate the a- 
mount which should be available for variations in feed; with doubl¬ 
ed capacity due to better feeding, power required will be increased 
about 50%. 

For finished products down to as fine as 16-mesh, rolls may be 
used to advantage, but where further reduction is required it is usu¬ 
ally better practice to reduce to about 34” m the rolls, and finish in 
ball, pebble, or rod mills. 

6 ft. Chilean Mills 




CAPACITY 




Fine Product 

Coarse Product 


R. P. M. 

Feed 





Horse 

Mesh 

Tons 

Mesh 

Tons 



Power 




Per Hr. 


Per Hr. 


29 

8 Mesh 

30 

3F5 

6 

7h 

50-90 

37 

2 Mesh 

30 

7 

6 

12 

75-120 


Water required: about 1 gal. P. M. per 24-Hr. Ton. 


























































CONSULTING ENGINEERS 


57 


Stamp Mills 


Weight 

, of 

Stamp 

Pounds 

DROPS 

CAPACITY 

Horse 

Power 

Per 

Stamps 

Inches 

Per 

Minute 

Fine Products 

Coarse Products 

Mesh 

Tons 

Per 

24 Hrs. 

Mesh 

Tons 

Per 

24 Hrs. 

850 

7-8 

90-106 

40 

4.3 

12 

6 

2.4 

1050 

6-8 

94-108 

30 

4.6 

3 

10 

2.6 

1250 

6-8 

90-110 

14 

5.4 

^2 

12 

3.0 

1500 

6 p 8 

96-100 

10 

8 

3 

14 

3.5 


Water required per Stamp : 3-10 gals, per minute ; about 1 gal. 
P. M. per 24-Hr. Ton. 


Cylindrical Ball Mills 

Capacities are for medium hard quartz and in closed circuit 
with classifier or screen. 


Size of Mill 
in Feet 
Dia. X 
Length 

Tons 

per 24 hrs. 
2" to 48 
Mesh 

Tons 

per 24 hrs. 
2" to 14 
Mesh 

H. P. 
Required 
to Run 

H. P. of 
Motor 
Recom¬ 
mended 

R. P. M. 
of 

Mill 

Ball 

Charge 

in 

Pounds 

3x3 

20 

30 

10 

15 

40 

1,200 

3x5 

30 

40 

15 

25 

40 

2,000 

4x4 

40 

75 

25 

40 

32^ 

3,000 

5x4 

60 

120 

40 

60 

28 

5,000 

5x5 

75 

150 

50 

75 

28 

6,500 

6x4 

120 

210 

60 

85 

24 

9,000 

6x5 

150 

260 

80 

100 

24 

11,000 

6 x 6 

190 

320 

100 

125 

24 

13,500 

7x5 

225 

375 

110 

125 

20 

18,000 

7x6 

275 

450 

135 

150 

20 

23,000 

8x5 

320 

500 

150 

175 

18 

25,000 

8 x 6 

385 

600 

180 

200 

18 

30,000 


From catalog, The Allis-Chalmers Mfg. Co. 


Conical Ball Mills 

Capacities given are for medium hard quartz ore and in closed 
circuit with classifiers or screens. 


Size of Mill 
Dia length 
Ft. In. 

Tons per 24 hrs. 
2" to 20 Mesh 

H.P.Req’d. 
to Run 

H. P. Motor 
Recomended 

R. P. M. of 
Mill 

Ball Charge 
in Pounds 

3x8 

8 

5 

71 

35 

1,000 

4^x16 

40 

18 

25 

33 

4,500 

5 x 22 

60 

30 

40 

29 

7,500 

6 x 22 

150 

50 

60 

26 

12,000 

7 x 22 

200 

75 

100 

24 

20,000 

7x36 

250 

85 

125 

24 

27,000 

8 x 22 

300 

110 

150 

22 

30,000 

8x36 

400 

150 

200 

22 

34,000 

8x48 

550 

200 

250 

22 

42,000 


From catalog. The Hardinge Co 






























































THE GENERAL ENGINEERING COMPANY 



Conical Pebble Mills 


Capacities given are for medium hard quartz ore and in closed 
circuit with classifiers or screens. 


Size of Mill 
Dia. length 
Ft. Inches 

Tons per 24 h 
feed to 28 
Mesh 

H. P. Req’d. 
to run 

H. P. Motor 
Recom¬ 
mended 

R. P. M. of 
Mill 

Pebble 
Charge 
in Pounds 

3x8 

6 

3 

5 

36 

300 

4±xl6 

20 

8 

m 

32 

2,500 

6x22 

45 

18 

25 

28 

4,500 

6x30 

55 

21 

30 

28 

4,800 

6x48 

70 

27 

35 

28 

5,500 

8x22 

100 

40 

50 

24 

10,000 

8x30 

125 

48 

60 

24 

11,000 

8x36 

140 

55 

60 

24 

12,000 


From catalog, The Hardinge Co. 


Cylindrical Pebble Mills (Tube Mills) 

Capacities are for medium hard quartz and in closed circuit 
with classifiers or screens. 

(Intermediate Lengths furnished every 2 feet; power, capacity, 
and pebble charge proportional) 


Size of Mill 

Tons 

H. P. 

H. P. 

It. P. M. 

Pebble 

In Feet 

per 24 hrs. 

Required 

Motor 

of 

Charge 

Dia x 

8 Mesh to 

to 

Recom- 

Mill 

in 

Length 

95 %-100M 

Run 

mended 


Pounds 

4x8 

25 

15 

20 

32 

5,000 

4x12 

29 

23 

30 

32 

7,500 

4x16 

38 

30 

40 

32 

10,000 

4x20 

40 

38 

50 

32 

12,500 

5x8 

42 

22 

40 

28 

7,800 

5x12 

50 

33 

50 

28 

11,800 

5x16 

59 

44 

50 

28 

15,700 

5x22 

75 

61 

75 

28 

21,500 

6x8 

55 

34 

50 

24 

11,300 

6x12 

71 

52 

75 

24 

17,000 

6x16 

90 

70 

100 

24 

22,600 

6x22 

118 

97 

125 

24 

30,200 

7x10 

85 

63 

75 

20 

19,200 

7x16 

120 

100 

125 

20 

30,800 

8x10 

112 

83 

100 

18 

25,100 

8x16 

186 

134 

150 

18 

40,200 


From catalog, Allis-Chalmers Co. 




































CONSULTING ENGINEERS 


59 


Revolving Screens 

(Trommels) 


Diam. 

Inches 

CAPACITY 

Length 

Ave 

Inches 

Horse 

Power 

R.P.M. 

Spray Water 
Gals. P. Min. 

Tons Per 24 Hrs.-1-12 Slope 

Y\" Deep 

Yi" Deep 

1 " Deep 

2" Deep 

Mm. 

2' Deep 

Yi' Deep 

1 " Deep 

30 

8 

24 

70 

200 

60 

0.33 

0.75 

16-22 

16 


36 

10 

30 

88 

240 

72 

0.50 

1.1 

16-20 

20 

10 

42 

12 

35 

100 

280 

84 

0.75 

1.6 

15-18 

24 

12 

48 

14 

40 

115 

320 

96 

1.1 

2.3 

14-17 

28 

14 

60 

18 

52 

145 

400 

120 

2.0 

4.0 

13-16 

36 

18 

72 


65 

180 

490 

144 

3.3 

6.0 

12-15 


23 

96 



220 

620 

192 

5.6 

9.0 

10-12 


28 


Capacities include all undersize, and are based upon the max¬ 
imum R. P. M. given. Minimum R. P. M. will reduce capacity a- 
bout proportionally. 

Depth of ore should be based upon hole in screen, between 2 
and 10 times the diameter of the hole, depending upon the quality 
of screening required (undersize in oversize). 

Capacity will vary as the slope: P er foot will have about 

half the capacity of the above, 2" per foot will have double the ca¬ 
pacity of the above, for the same conditions, with slightly better 
quality of screening on the flatter slopes. 

Length of screen has no appreciable effect upon capacity, but 
increased length should slightly improve quality. 

Horse Power will increase with the length. 

Present day practice turns to the use of the Vibratory type of 
Screen with its high ratio of capacity to floor space, and low power 
consumption. 

Inclined Impact Screens 

About 45° Inclination 

Capacity per sq. ft. screening area 

Mesh 6 8 10 14 20 28 35 48 65 100 

Tons, 24Hrs. 17 15 13 10 7 5 4 3 2 1 

Callow Traveling Belt Screen 

Capacity, 24" Duplex 

Mesh 6 8 10 14 20 28 35 48 65 100 150 

Tons, 24Hrs. 600 450 400 320 250 210 175 140 110 75 50 

Feed should carry 3^-4 tons water per ton ore. 

Undersize spray water: 6-10 gals, per minute. 

Oversize spray water: 8-12 gals per minute. 

To convert square hole screen( cloth or metal) into their equiv¬ 
alent in Millimeters: 

Square holes in inches x 33 = round holes in M. M. 

Round holes in M. M. x 0.0303 = square holes in inches. 

Square holes x 1.32 = round holes. 































60 


THE GENERAL ENGINEERING COMPANY 


Hydraulic Classifiers 

Hydraulic water: 5 - 20 tons per ton of ore. 

1 - 3.3 gals, per minute per 24-hour-ton. 

Callow Settling Tanks 

Capacities, on Dilute Slimes giving a Clear overflow and dis¬ 
charging a thickened pulp of 15% to 25% solids. 

Butte Slimes: 25 - 30 gals, per min. of feed 

Coeur D’Alene Slimes: 30 - 35 gals, per min. of feed 

Bingham Slimes: 35 - 40 gals, per min. of feed 

As Feed Desliming Tanks for Tables - 30 Mesh Feed in 4% or 
5 to 1 water. 50 tons solids per 24 hours, contained in 35-40 gals, 
per min. 

Products: Overflow 3%% Solids; Thickened Pulp 33% (67% 

moisture). 

Thickening Tanks 

Flotation Concentrates, 5-10 Sq. Ft. Per 24-Hr Ton of Solids 
Slimes (Cyanide Plants), 3-10 “ “ “ “ “ " “ 

Easy Settling Ores, 3-6 

Difficult “ “ 10-40 “ “ “ “ “ “ “ 

Vacuum Filters—Continuous 

Built in various sizes from 4’ Diam. with 4 sq. ft. filtering area 
up to 14’ Diam. with over 600 sq. ft. filtering area. 

Capacity depends upon physical condition of the solids (Col¬ 
loidal or Granular), screen analysis, amount of water to be removed, 
etc. 

Feed: Flotation concentrates, 50% moisture; cake: 10 - 15% 
moisture, 3 to 7 sq. ft. filtering area per 24 hr-ton of solids. 

Vacuum Pump Capacity:—From 0.75 to 1.00 cu. ft. displace¬ 
ment for each square foot of Filter area, at 20 to 22 inches (mercury) 
vacuum. 

Concentrating Tables and Vanners 


Feed 

Capacity 
Tons Per 
24 Hrs. 

Minimum 
Ratio of 
Water To 
Ore In 
Feed 

Wash- 

Water 

Per 

Machine 
G. P. M. 

Tables 

Unclassified — 2\ m. m 

75-150 

1.5 to 1 

10-15 

Unclassified —20 Mesh 

15-60 

2.5 to 1 

8-12 

Unclassified —60 Mesh 

10-30 

3.0 to 1 

6-10 

Screen or Classified+30 
Screen or Classified+120 

25-50 

10-25 

} 3.0 to 1 

5-10 

Vanners 
—20 Mesh 

5-10 

5 to 1 

3-5 

—200 Mesh 

3-5 

4 to 1 

1.5-3 


Manners are little used since the adoption of flotation. 



















CONSULTING ENGINEERS 


61 


Hartz Jigs 


Feed 

Sizes 

Mesh 

No. 

Compts 

18"x36" 

Water 

Gals. 

Per Min. 

Capacity 

Tons 

Per 24 Hrs. 

Horse 

Power 

8-14 

4 

8-16 

5-15 

3 

4-6 

3 

15-20 

8-20 

2! 

2-3 

2 

18-30 

10-30 

2 

MM 

15-25 

1 

20-30 

15-50 

U 

25-50 

1 

30-50 

30-100 

H 


Flotation Type Rotary Blowers 


Size 

Cu. Ft, 


Horse Power 

Outlet 

No. 

Per Min 

R. P.M. 

5 lbs. 

3^ lbs. 

Inches 


100 

420 

4.6 

3.5 

5 

4 

200 

615 

6.7 

5.0 

5 


200 

455 

7.1 

5.3 

5 

2 

250 

530 

8.3 

6.2 

5 

1 

300 

305 

10.6 

8.0 

6 

500 

440 

15.3 

11.0 

6 


600 

335 

19.1 

14.0 

8 

2 

800 

415 

23.6 

17.5 

8 


900 

275 

27.1 

20. 

10 

3 

1400 

390 

38.4 

28. 

10 


1600 

290 

45.4 

33. 

12 

4 

2200 

380 

59.4 

43. 

12 


2400 

290 

65.0 

48. 

14 

5 

3000 

345 

81.5 

60. 

14 


3000 

245 

81.0 

60. 

16 

5j 

3800 

315 

101.0 

75. 

16 

6 

4000 

235 

107. 

80. 

16 

4600 

270 

122. 

90. 

16 


Adapted from catalog, P. H. & F. M. Roots Co. 

Above table based upon free air at sea level. Capac'ty given is 
for 5 lbs. pressure, and will be increased slightly for V /2 lbs. pres¬ 
sure. Horse-power will be reduced slightly as altitude increases. 
For combustion purposes at higher altitudes, additional capacity 
must be provided to equal sea-level conditions; but for flotation 
purposes, such allowance is unnecessary. 

Pneumatic Flotation 

Capacity is for iy 2 to 2 tons of feed per square foot of aerating 
surface per 24 hours. 

Air required is approximately 10 cubic feet of free air per min¬ 
ute per square foot of aerating surface, at 3 1 /? lbs. per square inch 
for flat bottom and 5 lbs, for sloping bottom cells. 

Pul]) for pneumatic flotation should usually carry from 20 to 25 
per cent solids. 






























62 


THE GENERAL ENGINEERING COMPANY 


Drying Ores and Concentrates 


(Condensed from Ruggles-Coles Eng. Co. Cat. No. 16) 
HEAT AND COAL TO DRIVE OFF MOISTURE (Theoretical) 
PER TON (2,000 lbs.) OF DRY MATERIAL 




At 100% Efficiency 



At 100% Efficiency 

Moisture 

Water 

Total 

Coal 

Moisture 

Water 

Total 

Coal 

% 

Lbs. 

B. T. U. 

Lbs. 

% 

Lbs. 

B. T. U. 

Lbs. 

1 

20 

86,200 

7.2 

25 

667 

809,550 

67.5 

2 

41 

109,680 

9.2 

30 

857 

1,021,970 

85 

4 

83 

156,630 

13.1 

35 

1,077 

1,267,930 

106 

6 

128 

207,940 

17.7 

40 

1,333 

1,554,130 

130 

8 

174 

258,370 

21.5 

50 

2,000 

2,299,840 

193 

10 

222 

312,040 

26.0 

60 

3,000 

3,417,840 

285 

12 

273 

369,050 

30.8 

70 

4,667 

5,280,430 

440 

14 

325 

427,190 

35.6 

80 

8,000 

9,007,840 

756 

16 

381 

489,800 

40.8 

85 

13,333 

12,734,090 

1,060 

18 

439 

554,640 

46.2 

90 

18,000 

20,188,000 

1,680 

20 

500 

622,840 

52 

95 

38,000 

42,548,000 

3,550 


Total B. T. U. include 63840 B. T. U. to raise temperature of 
material from 60 deg. F. to 212 deg F. at which point evaporation 
takes place (at sea level) ; specific heat of material taken as 0.21 

Coal assumed to have 12000 B. T. U. per lb. as used and is for 
100% per cent efficiency as specified. Efficiencies in drying vary 
widely, depending upon the method of applying heat, the type of 
apparatus, etc., probably from 25% to 75%. Table of coal added to 
original data by General Engg., Co. 


Belt Conveyors 


belt 

Material 


Max. Lengths 


Tons 
Per Hr. 
100 

F.P.M. 

Horse 

Power 

100 

F. P. M. 

Max. 

Belt 

Speed 

F. P. M. 

Width 

Inches 

Ply 

Ave. 

Max. 

Sizes 

* 

Wt. 
Cu. Ft. 






Horiz. 

1-12 

X 

X 

M 


5 

Deg 
9 H 

rees 

14 

18 1 /2 

12 

3 


50 

700 

520 

410 

340 

280 

11 

2.2 

300 




100 

500 

325 

245 

195 

160 

22 



16 

4 

2M-4 

50 

730 

530 

400 

340 

285 

20 

3.8 

300 




100 

520 

330 

240 

195 

160 

40 



20 

4 

3K-5 

50 

610 

450 

325 

280 

245 

31 

4.8 

400 




100 

435 

280 

200 

160 

135 

62 



24 

5 

4M-8 

50 

685 

490 

375 

305 

250 

46 

7.6 

450 




100 

490 

310 

225 

175 

140 

92 



30 

6 

6-12 

50 

670 

465 

350 

290 

245 

75 

11.5 

500 




100 

480 

290 

210 

165 

135 

150 



36 

6 

7H-15 

50 

645 

450 

325 

260 

235 

105 

14.5 

500 




100 

460 

280 

195 

150 

130 

210 



42 

7 

9-18 

50 

690 

465 

340 

275 

230 

140 

20 

600 




100 

490 

290 

200 

155 

125 

280 



48 

8 

10-20 

50 

715 

465 

335 

280 

235 

185 

25.5 

600 




100 

510 

290 

200 

160 

130 

370 




* Smaller figure is for sized material, larger for run-of-mine. 
For other plies of belt, max. length and power proportional. 
For other speeds, capacity and horse power proportional. 


Adapted from catalog of Dodge Sales & Engineering Co. 



























































CONSULTING ENGINEERS 


63 


H. P. Required for plain Cylindrical Dryers 


Diam. 

Length 

R. P. M. 

H. P. 

R. P. M. 

H. P. 

4^x40' 

4 

10.5 

5 

13.5 

5' x50' 

3 

14.5 

4 

19.1 

6' x60' 

01 

^2 

27.0 

3 

32.2 


Belt and Bucket Elevators 


Spacing = twice the projection of Bucket from Belt. 





Head 



Horse 


Belt 

Max. 

Pulley 


Tons 

Power 

Bucket 

Plies 

Lift 

Diam. 

R. P. M. 

Per Hr. 

For 



Feet 

Inches 



Max. Lift 


10 

95 

80 

29 

180 

34 

24x8 

8 

80 

64 

32 

160 

25 


5 

50 

40 

40 

125 

13 


8 

80 

64 

32 

130 

21 

20x8 

6 

60 

48 

37 

110 

13 


4 

40 

32 

45 

90 

7 


8 

75 

64 

32 

105 

16 

16x8 

6 

60 

48 

37 

90 

11 


4 

40 

32 

45 

75 

6 


8 

95 

64 

32 

77 

14 

14x7 

6 

75 

48 

37 

65 

10 


4 

50 

32 

45 

55 

5.5 


8 

105 

64 

32 

58 

12.2 

12x6 

6 

80 

48 

37 

49 

7.8 


4 

50 

32 

45 

40 

4.0 

10x6 

6 

80 

48 

37 

41 

6.6 

4 

55 

32 

45 

34 

3.8 

8x5 

6 

90 

48 

37 

27 

4.9 

4 

60 

32 

45 

22 

2.7 

6x4 

% 

5 

90 

40 

40 

16 

2.7 

3 

45 

24 

52 

12 

1.2 


The tonnage and horsepower in the above table are based upon 
the buckets being: 

25% Full of Dry Material, 100 lbs. per cu.ft., or 

50% Full of Dry Materials, 50 lbs. per cu. ft, or 

40% Full of water and lesser amounts of pulp. 

This provides liberal allowance for feed variations. 

Speeds (R. P. M.) Give centrifugal discharge for the corres¬ 
ponding pulley diameters. 

It is usual in mining practice to use greater number of plies of 
belt, to allow for wear. 

Adapted from catalog of Dodge Sales & Engineering Co. 
































64 


THE GENERAL ENGINEERING COMPANY 


Strength of Timber 
Table I 

Unit Stress in Pounds per Square Inch. 
(Americal Railway Engineering Association, 1909) 


Bending 


shearing 


Compression 


Kind of 
Timber 

Extreme 
Fiber Stress 

Modulus 

of 

Elastcity 

Parallel to 
the Grain 

Longitudinal 
Shear 
in Beams 

Perpendicular 
to the 
Grain 

Parallel 
to the 
Grain 

Working 
Stresses for 
Columns 

Average 

Ultimate 

W'orking 

Stress 

Average 

Average 

Ultimate 

1 

Working 

Stress 

Average 

Ultimate 

Working 

Stress 

Elastic 

Limit 

Working 

Stress 

Average 

Ultimate 

Working 

Stress 

Length 

Under 15xd 

Length Over 

15xd ■+ 

Douglas Fir 

6,100 

1,200 

1,510,000 

690 

170 

270 

110 

630 

310 

3,600 

1,200 

900 

1,200 

Longleaf Pine 

6,500 

1,300 

1.610,000 

720 

180 

300 

120 

520 

260 

3,800 

1,300 

975 

1,300 

Shortleaf Pine 

5,600 

1.100 

1,480,000 

710 

170 

330 

130 

340 

170 

3,400 

1,100 

825 

1,100 

White Pine 

4,400 

900 

1,130,000 

400 

100 

180 

70 

290 

150 

3,000 

1.000 

750 

1,000 

Spruce 

4,800 

1,000 

1,310.000 

600 

150 

170 

70 

370 

180 

3,200 

1,100 

825 

1,100 

Norway Pine 

4,200 

800 

1,190,000 

*590 

130 

250 

100 


150 

*2,600 

800 

600 

800 

Tamarack 

4,600 

900 

1,220000 

670 

170 

260 

100 


220 

*3,200 

1,000 

750 

1,000 

Western Hemlock 

5.800 

1,100 

1,480,000 

630 

160 

*270 

100 

440 

220 

3,500 

1,200 

900 

1,200 

Redwood 

5,000 

900 

8,000 

300 

80 



400 

150 

3,300 

900 

675 

900 

Bald Cypress 

4,800 

900 

1.150.000 

500 

120 



340 

170 

3,900 

1,100 

825 

1,100 

Red Cedar 

4,200 

800 

800,000 





470 

230 

2,800 

900 

675 

900 

White Oak 

5,700 

1,100 

1.150.000 

840 

210 

270 

110 

920 

450 

3,500 

1,3001 975 

1.300 


Li 

t Multiply values in last column by (1-). 

60 d 

Above stresses are intended for railroad use. For highway bridges and 
trestles increase 25%. For structures protected from weather and free from 
impact, increase 50%. For deflection under long continued loading use 
50% of the corresponding modulus of elasticity. Above stresses are for 
green timber and are to be used without increasing the live load stress for 
impact. Values noted * are for partially air dry timber. Building laws of 
various cities specify maximum loads slightly at variance with above 
figures, both higher and lower. The above figures, however, may be safely 
followed. In the formula for columns, 1 = length of column in inches, d 
= least side or diameter in inches. 

Table III 

Unit working stresses in pounds per square inch, long columns. 

z 

White Pine or Tamarack, 1,000 (1 -) pounds per sq. inch. 

d60 


Effective length col. in inches 
Least side or dia. in inches 

15 

16 

17 

18 

19 

20 

21 

22 

23 

24 

25 

26 

27 

28 

29 

30 

Working Stress 

750 

733 

717 

700 

683 

667 

650 

633 

617 

600 

583 

567 

550 

533 

517 

500 


White Pine or Tamarack was selected because the working stress for 
compression perpendicular to the grain is 1000 pounds. For other woods 
select the corresponding values from Table I above, and increase or de¬ 
crease proportionally. For rectangular columns take the safe load unit 
stress for the square column whose side is equal to the least side of the 
rectangular section, and increase proportionally. For round column, take 
the safe load unit stress for the square column whose side is equal to the 
diameter of the round column and multiply by the decimal 0.78. 

(Carnegie) 




























































































CONSULTING ENGINEERS 


65 


Strength of Timber 


Table 11 

Safe load in pounds, uniformly distributed, for rectangular 
Spruce beams. Max. bending stress, 1000 pounds per sq. inch. 


Size of 
Timber 
Inches 

Max 
Bending 
Moment 
Ft. lbs. 

Limit 
for Shear 
Short 
Lengths 

2x4 

445 

746 

6 

1,000 

1,120 

8 

1,775 

1,494 

10 

2,795 

1,866 

12 

4.000 

2,240 

3x6 

1,500 

1,680 

8 

2,670 

2,241 

10 

4,190 

2,799 

12 

6,000 

3,360 

14 

8,190 

3,921 

16 

10,660 

4,479 

4x6 

2,000 

2,240 

8 

3,555 

2,988 

10 

5,555 

3,732 

12 

8,000 

4,480 

14 

10,900 

5,228 

16 

14,200 

5,972 

18 

18,000 

6,720 

20 

22,200 

7,468 

22 

26,900 

8,212 

24 

32,000 

8.960 


Distance between supports, in feet 


6 

8 

10 

12 

14 

16 

18 

20 

22 

24 

592 

444 

1.000 

356 

800 

1,422 

296 

666 

1,186 

1,852 







572 

1016 

1,588 

500 

888 

1,388 

2,000 

750 

1,332 

2,082 

3,000 






790 

1,234 

1,778 

712 

1,112 

1,600 





1,010 

1,454 

926 

1,334 





1,500 

1,200 

2,133 

999 

1,779 

2,778 

858 

1,524 

2,382 


1,185 

1,851 

2,667 

3,630 

1,068 

1,668 

2,400 

3,267 

4266 





1,515 

2,181 

2,970 

3,879 

1,389 
2,001 
2 721 
3,555 
















2,000 

1,600 

2,844 

1,332 

2,372 

3,704 

1,144 

2,032 

3,176 

1,000 

1.776 

2.776 
4.000 



1,580 

2,478 

3,556 

4,840 

1,424 

2,224 

3,200 

4,356 

5,688 





2,020 

2,908 

3,960 

5,172 

6,544 

1,852 

2,668 

3,628 

4,740 

6,000 

7,408 


















































*These figures meet the New York building requirements for 
oak and of Boston for white pine, spruce and oak. 

Spruce was selected to list in the above table because the work¬ 
ing stress for bending (as per table I) is 1000 pounds. For other 
woods, select corresponding values from Table I above and increase 
or decrease proportionally. For other sizes select a timber from the 
table of same depth and increase or decrease proportionately with 
width of timber. For other lengths, allowable loads may be figured 
from “maximum bending moments” as listed above. 

For concentrated load at center,safe load is half the above. 


Table IV 


Safe loads in pounds on square wooden columns. 
White Pine or Tamarack 


Length in 1 
Feet 

side of Square, Inches 



4 

6 

8 

10 

12 

14 

16 

17 

20 

5 

6 

7 

8 

9 

10 

11 

12 

14 

16 

18 

20 

12,000 

12,000 

11,200 

10,400 

9,600 

8,800 

8,000 

























27,000 

26,400 

25.200 

24,000 

22,800 

21,600 

19.200 

48,000 

48,000 

46.400 
44,800 

41,600 

38.400 
35,200 
32 000 

75,000 

Working Strain = 

( 1 ) 

1000(1-)pounds 

( d60 ) 
per sq. inch. 

Loads above horizontal 
lines are maximum 
allowable safe loads. 



72,000 
68,000 
64.000 
60 000 

108,000 

105,600 

100,800 

96.000 




147,000 

145,600 

140.000 






192,000 

192,000 

243.000 

300 000 



























































































































66 


THE GENERAL ENGINEERING COMPANY 


Principal Economic Minerals 


M INERAL 

SPEC. 

GRAY 

HARO- 

NESS 

COM PO 
Formula 

5ITION 

PER. CENT 

ANTI MONY 





STiBNlTE 

4.55 

2 

5 b 63 

Sb-71.4, 5-23.6 

COPPER 





AT AC AM iT£ 

* O chlor idz 

3.75 

3-3.5 

Cu C/£ 3Cu(OH^2 

Cu-59 5, 0-16.6, OH-23-5 

AZURITE. 

Carbonate. 

3. 78 

3.5-4.5 

Z Cu lO-j Cu (Oh)^ 

Cu-55.3, 0-13.9, 

CO^- 25 5, tit 0-5.2 

BORN iTE 

Variegated , Peocoe it- 

5. >5 

3 

CU 5 Fe. 5 4 , 

(or Cuj ?e ) 

Cu - 63.3, Peril.l, 3-25.6 

BROCHANTITE 
-Soi'C Su I pnatt 

3.3 

3.5*4 

Cu50 4 3Co (oh )2 

Cu -66 2 , SO 4-25 0 OH-&a 

Chalcocite 

Glance 

5.65 

25-3 

Cu 2 5 

Cu-79.9, 5-20/ 

CMALCOPr RITE 

Copper P y ntC5 

4.2 

3-5-4 

Cu Fe 5i 

Cu -34.6, F«-3A4, 5-35.b 

Cmrysocolla 
* Si 1 IcatC 

2.1 

2-4 

Cu 3'Uj 2 H-O 

Cu-36. 1 , Si Oj-34.3, 0-4 1 
Hi 0-70.5 

COVE L LITE 

Indigo 

4.6 

1-5-2 

CuS 

t 

Cu-66-5, S-33-3 

CUPRITE 

-Red 0*id£, Rubs'- 

6.0 

3 5-4 

0 

c 

O 

Cu-88.5, O-il.2 

EnargitE 

-Sul pn - Ai-ssnate 

4-45 

3 

Cu^ A* 5* 

Cu-48.4, AS-15.0, 

5-32. 6 

Malachite 

-Green Carbonate 

4.0 

3.5-4 

CuCOj Cu (,OH)j 

Cu-57.5, 0-/4. 5 
COi-19.9 , HiO- 6.1 

Melacomte 

-Slock o*idC 

5.95 

3 

CuO 

Cu-74-4, O’20.1 

tetrahedrite 

GrOy Copper 

4.15 

3-4.5 

4Cu i S_Sb^Sj 

t^fa, Pk 2*, Aq* 

Cu-52-2, 5b* 24-7,. 
5-23-1 

IRON 





HEMATITE 

specular iron 

Iron Ok idc 

5.1 

5.5-6.5 

Fe z O, 

Fc-69.9, 0-30-1 

LlMONITE 

Brown Hematite, B 09 Ora. 

magnetite 

Magnetic, 0*idc 

3-6-4.0 

5. 17 

5-5.5 

5.5-65 

2 Fe t O* 3H 2 0 

Fe j 0 A 

Fe-59.fi, 0-25.7, 

fe-72-4, 0-27.6 

ARSENOPYRITE 

6.05 

5 5-6 

Fe- As S 

Fc -43.7, As-31.2, 5-251 

MARCASITE 

White Pyritae 

PYRlTE 

Pyrites 

4.9 

54 

6-6.5 

FeS, 

Fa 46 33, §- 33-45 















CONSULTING ENGINEERS 


67 


Principal Economic Minerals 


mineral 

SPEC. 

HARD' 

COMPOSITION 

GRAV 

NESS 

formula 

PER CENT 

IRON- C0NT0. 





PyRRHOTITE 

4.65 

35-45 

fit// S>t 

fa-61.5, S-5B.5 

Yagnat i’c Pyr'iiCt 




Side.® ite 

3.85 

5-45 

fa. CO 3 £>, My 


Spathic (ran 





LEAD 





anglesite 

6.1 

2.15-5 

Pb SO* 

Pb‘6B.5, 5-10.6, 

-Sulphate 




O-ZI.I 

CERRUSSlTE 
-C Qrbonata 

6.55 

5-3.5 

Pb C0 3 

Pb-77.5. 0-6.0, 

C Ox - / 0 .5 

Galema 
•S ul ph .de- 

7.45 

2.5 

Pb 5 

Pb-36.6, 5-15.4 

MANGANESE 





PrffouuSlTC 

-Oioxidft 

4-.B2 

1-25 

Mn Ox 

Mn-63.1, 0-36.6 

?S)LOMLLASlB 





RhOOON/TE. 

3.5 


Mn 5 ! Ox 

Mn-47.7, S\O t -52.2> 

-Si Heatc 





RhU 00 CHRoSiT£ 

-Darfranat* 

3.5 


MnCO a 

MnO-6i.lt CO t - 38.3 

MaNGAW(T£ 

4.3 


Mn j Oj HjO 

Mn-62.3, O- 27.3 



• 

HjO.io.l 

mercury 





Cinnabar 

8 . l 

2-2.5 

S 

H 9 -S 6 .Z, 5-13.8 

-Suifhioe 



MOLYBDENUM 





MOLYB0ENIT£ 

-Su Iphidc 

4.75 

1-1.5 

Mo5 2 

Mo ‘59.95, S -AO.05 

Wulfem/te 



Pb MoO A 

?t>-5* .4, Md- 2 *. 2 , 

0-17.4 

Lead Molybdai* 

6 05 

3 

SI LVER 





ARGENTITE 

7.3 

2'2.5 

A$ % S 

Ag -8 7.1, S-12.9 

•Glance 





cerargyrite 

5.55 

1.5-2 

Ag Cl 

Ag*75'3, Cl * 24-7 

Horn Silver 





Proust ite 

5.6 

2.5 

AejA» 5> 

>Vj- 65.4, A3-I5.2 

Red - Hvby Silver 




S-19.4 

PY RARGYRlTE 

5.8 

7-2-5 

Ag 3 Sb S 3 

Ag"3S.9, 56-22-3 

Ruby Silver 



5- 17.8 

Stephanite 

•Sulph* Anti man i’te 

6 2 

2-2 5 

A<35 5b -^4 

Ad-68.5* 5b- i5-3 

5 - 16 .3 

5ylvaniT£ 

8 . i 


Au Tc z 


Tcilur.de 




----I 














68 


THE GENERAL ENGINEERING COMPANY 


Principal Economic Minerals 



SPEC. 


COMPOSITION 

Mineral 

OR av 

NE5S 

formula 

PER CENT 

T 1 N 





CASSlTERlTE 

6.95 

6-7 

5 n 0 2 

Sn-7g-8, 0-21-2 

T .n btohC 





TUNGSTEN 





WOLFRAM ITE 

735 

5 -5.5 

(Ft., Mn) VVO 4 . 

(Pc.rib-30.9, IV-51-3 


7 35 


0-17.8 

HUBNERITE 

45 

Mn SV0 4 

Mn-ig.i, W- 60.7, 




0-211 

SCMEELITE 

6.0 

4.5-5 

Ca WO 4 

CoO- 19.5, W-63.3 




0 -/ 6 .7 

ZINC 





Calamine 

3.45 

4.5* S 

2 ZnO 5i 0*H t O 

Zn-542, S,0 2 -38.3 

-Hydrous Stlf'cot* 



HiO- 7.5 

MARMATITE 

3.9-4 .2 

5 

(Zn Pc)S 

Zn ±4.2.7, to. ± 36.4 

Iron Blende 




5-20.9 

SM ITWSON ITE 

4.35 

5 

Zn CO 3 

Zn -52.1, C-9.6 ' 

-Carbonate 



0-30.3 

SPHALERITE 

4.0 

3.5-4 

Zn S 

Zn- 67 1 , 5-31-9 

Blen4e, Jack. 
WILLEMlT E 

4.0 

5.5 

2 ZnO, SiO z 

Zn-35.6 , 5iO x -4/.4 

-561 csi« 




ZINCITE 

5.5 

4-45 

ZnO 

Zn-So,3, 0-19.7 

-O* rde 





GRAPHITE 

ZJ5 


c 


- Slock Load 





GANGUE 





Anhydrits 

Z. 95 

3-3.5 

Ca 504 

CaO- 41.2, 5O.J-50.S 

- Anhydrous Sulphate 

Sarite 

4.5 

2 > 5 - 3.5 

Ba S 0 4 

5a 0-35.1, SO 3 -34.3 

Bar/ta, Heavy Spar 




CALCITE 

Z7Z 

3 

Ca CO 3 

CaO- 56 . 0 , C0 2 -44.0 

bpar."Li'ne, Limestone 




DOLOMITE, 

MagnCfiuni Limestone 

2.05 

35-4 

Ca Mg(C 0 3 ) 2 

Ca 0-30.42. MaO-2I.S 
CO r 47-7 

Gypsum 

-Hydrou* 5u Iphata 

2-32 

1.5- 2 

Ca SO4 2 H z O 

CjO-32-6, SO3-43.5 
MiO-ZO.9 

MAGNESITE 

- Carbonate 

3.1 

3*4.5 

M 9 CO 3 

Mg 0-47.8, C0 2 -32.2 

quartz 

2.65 

7 

s;o x 

S» * 46. 9, O -53. 1 

Si Itca 





\A<nou$ Common 

2-5 <0 




Cangue Silicates 

3 5 














CONSULTING ENGINEERS 


69 


A list of Minerals, their Description and Specific Gravity 

Spec. Gray. 


Aluminum.. 

Andalusite. 

Anglesite. 

Anthracite. 

Antimony. 

Apatite. 

Aragonite. 

Argentite. 

Arsenic. 

Arsenolite. 

Asphaltum.... 

Atacamite.. 

Azurite. 

Barite. 

Bauxite. 

Beryl. 

Biotite. 

Bismuth. 

Bismuthinite 

Bituminous 

Bornite. 

Cadmium. 


,A1. 

•Al 2 SiO s . 

.PbSO„. 

4 

Sb. 

-3Ca 3 P 2 0 8 ,CaF 2 

-CaC0 3 . 

-Ag 2 S.... 

..As. 

-As 2 0 3 . 


.CuC1 2 3Cu(OH) 2 .„ 

,Cu 3 (0H) 2 (C0 3 ) 2 

..BaS0 4 . 

,.A1 2 0 3 2 H 2 0. 


.Bi. 

.. 

Coal. 

.Cu 2 FeS 3 

.Cd.. 


Calamine. 

Calcite. 

Cassiterite.... 

Cerargyrite... 

Cerussite. 

Chalcocite. 

Chalcopyrite 

Chromite. 

Chromium.... 

Chrysolite. 

Cinnabar. 

Cobalt. 

Cobaltite. 

Copper.. 

Corundum- 

Cryolite. 

Cuprite. 

Cyanite. 

Diamond. 

Dolomite. 


H 2 Zn 2 SiO s . 

.CaCO.. 

-Sn0 2 . 

• AgCl.,. 

•PbC0 3 . 

-Cu 2 S. 

.CuFeS 2 . 

FeCr 2 6 4 . 

.Cr. 

,.(MgFe) 2 Si0 4 
-HgS. 


.CoAsS. 

.Cu. 

-Ai 2 o 3 . 

.Na A1F. 

-Cu.,0. 

•Al 2 Si0 5 . 

c. 

(CaMg)C0 3 


Enargite 

Epidote.. 


CuAsS 4 . 

HCa (AlFe) 3 

Si^Oia. 


. 2.60 

.Silicate of aluminum.3.16—3.20 

.Lead sulphate .6.12—6.39 

.Hard Coal ..1.32—1.70 

. 6.71 

.Phosphate of lime .3.17—3.23 

.Carbonate of lime . 2.94 

.Silver sulphide ..7.20—7.36 

.. 5.78 

.White arsenic .3.70—3.72 

.1.0 —1.80 

.Chloride of copper . 3.75 

.Blue carbonate of copper.3.77—3.83 

.Barium sulphate .4.3 —4.6 

..Hydrate oxide of aluminum 2.55 

..Silicate of beryllium.2.63—2.80 

..Magnesia-iron mica .2.70—3.10 

. 9.80 

..Sulphide of bismuth .6.4 —6.50 

..Soft coal .1.14—1.43 

..Sulphide of copper and iron..4.90—5 43 

. 8.60 

..Silicate of zinc .3.40—3.50 

..Carbonate of lime . 2.7 

..Dioxide of tin .6.8 —7.10 

..Horn Silver . 5.55 

..Carbonate of lead .6.46—6.57 

..Copper glance .5.5 —5.8 

..Copper pyrite .4.1 —4.3 

..Chromic iron .4.32—4.57 

. 650 

..Silicate of magnesia and iron3.27—3.37 

..Sulphide of mercury .8.0 —8.2 

. 8.6 

..Sulph-arsenide of cobalt.6.0 —6.30 

.8.8 —8.90 

...Oxide of aluminum.3.95—4.10 

..Fluoride of aluminum & sodium 3.0 

...Red copper ore .5.85—6.15 

...Aluminum silicate .3.56—3.67 

. 3.50 


Carbonate of lime and 

magnesia .2.80—2.90 

. 4.45 

Silicate of iron alumina 

and lime .3.25—3.5 





















































































































70 


THE GENERAL ENGINEERING COMPANY 


Fluorite.CaF. ( 

Frankl inite. 


Galena. 

Garnet. 

Gold. 

Graphite. 

Gypsum. 

Hematite. 

Ice. 

Iodyrite. 

Iridium. 

Iron. 

Kaolinite. 

Lead. 

Limonite. 

Magnesite. 

Magnetite. 

Malachite. 

Manganese. 

Manganite. 

Monazite. 

Marcasite. 

Mercury. 

Millerite. 

Mimetite. 

Muscovite. 

Naphtha. 

Niccolite. 

Nickel. 

Opal. 

Orp’ment. 

Orthoclase. 

Ozocerite. 

Palladium. 

Platinum. 

Proustite. 

Pyrargyrite. 

Pyrite. 

Pyrolusite. 

Pyromorphite. 

Pyrrhotite. 

Quartz. 

Realgar. 

Rhodochrosite 

Rhodonite. 

Rutile.. 

Serpentine. 

Siderite. 


PbS 


... Au. 

..C. 

..CaS0 4 -f-2H 2 0. 

- F e 2 0 3 . 

~H„0. 

..Agl. 

Ir. 

Fe. 

„2H o 0Al o 0„2Si0 2 

„Pb. 

,2Fe o 0 3 3H 0 0. 

-Mgco,.. 

..FeO,Fe 0 0 3 . 

Xu 2 (OH) 2 'co 3 . 

..Mn. 

-Mn 2 0 3 H 2 0. 


3 . 

Hg. 

NiS. 

SFb.As.O.PbCl, 

H„KAl~(Si0 4 ) 3 ... 


NiAs. 

Ni. 

SiO ? nH 2 0 
As 2 S 3 . 

KAlSigOg.. 


..Pd. 

..Pt. 

-Ag,AsS s . 

.. Ag.,SbS. ( . 

...FeS 2 . 

-MnO,. 

..3Pb,P 2 0 8 PbCl 0 
Fe S 

1 . 

-Si0 0 . 

.AsS. 

.MnCO^. 

.MnSiO‘ 3 . 

TiO,....:. 

. H.Mg.,Si 0 0 0 . 

.FeC0 3 . 


..Fluor spar . 3.2 

..Oxide of zinc, manganese 


and iron .5.07—5.22 

..Sulphide of lead . 7.43 

..3 15—4.3 

.15.6—19.3 

...2.09—2 23 

...Sulphate of lime . 2 3 

..Red oxide of iron .4.90 —5.3 

. 0.915 

..Iodide of Silver .5.6—5.7 

. 22.42 

.. 7.85 

..Silicate of alumina . 2.6 

. 1137 

.Brown oxide of iron .3.6 —4 0 

-Carbonate of magnesia .3 0 —3.12 

..Magnetic oxide of iron .5.16—5.18 

..Green carbonate of copper..3 9 —4.0 

-. 7.39 

..Hydrate manganese oxide ....4 2 —4.4 

.4 8 —5.1 

..White iron pyrite .••.4.85—4 90 

. 13.6 

..Nickel sulphide .5 3 —5.6 

..Lead arsenate .7.0—7.25 

.Potash mica .2.76—3.0 

.. 0.60—0.756 

.Nickel arsenide .7.33—7.67 

. 8.9 

.1 9 —2.3 

.Yellow sulphide of arsenic..3.4 —3 5 

.Potash Feldspar .2.46—2.6 

.Mineral wax .0.85—0.90 

.. li.3_n.B 

. 14.0—19.0 

..Light red silver ore.5.57—5.64 

.Dark red silver ore.5.57—5.86 

.Iron sulphide .4.95.—5.10 

.Dioxide of manganese . 4 82 

.Lead phosphate .6.5 —7.1 

.Magnetic pyrite .4.58—4.64 

.. 2.65—2.66 

.Red sulphide of arsenic . 3.55 

.Carbonate of manganese.3.45—3.6 

..Silicate of manganese.3.40—3.68 

Dioxide of titanium . 4 2 

.Silicate of magnesia .2.50—2.65 

.Carbonate of iron .3.8 —3.9 





























































































































CONSULTING ENGINEERE 


71 


Silver. 

Smaltite.. 

Smithsonite.. 

Sphalerite. 

Spinel.. 

Stephanite.... 

Stibnite. 

Sulphur. 

Sylvanite. 

Talc. 

Tephroite. 

Tetrahedrite 

Tin. 

Topaz. 

Tourmaline.. 

Willemite. 

Wolframite.. 

Wulfenite. 

Zinc. 

Zincite. 

Zircon. 


-Ag. 

..CoAs,,. 

..ZnCO. 

..ZnS. 

-MgAl 2 0 4 . 

- A &5 S 4 Sb . 

-Sb 2 S s . 

S. 

.,(Au,Ag)Te 2 ... 

• H 2 Mg 3 Si 4 0 12 

..Mn 2 Si0 4 . 

..4Cu 2 S,Sb 2 S 3 ... 
,.Sn. 


.. 10 . 1 — 11.1 

..Arsenide of cobalt .6.4 —6.6 

..Carbonate of zinc .4.30—4.45 

.Sulphide of zinc .3.9 —4.0 

.Aluminate of magnesia .3.5 —4.1 

..Brittle silver .6.2 —6.3 

.Sulphide of antimony .4.5 —4.6 

. 2.08 

..Telluride of gold and silver..7.9 —8.3 

.Silicate of magnesia .2.7 —2.8 

..Silicate of Manganese .4.0 —4.1 

..Gray copper .4.4 —5.1 

. 7.29 


Zn o Si0 4 . 

(Fe,Mn) WO. 

PbMoO.. 

4 

Zn. 

ZnO. 

ZrSiO.. 

4 


Fluo-silicate of alumina .3.4 —3.6 

Silicate of alumina, iron and 

magnesia .2.98—3.20 

Silicate of zinc .3.9 —4.18 

Tungstate of iron and 

manganese .7.2 —7.5 

Molybdate of lead .6.7 —7.0 

. 7.15 

Zinc oxide .5.43—5.7 

Silicate of zerconium.•• 4.70 


Areas and Circumferences of Circles 


Dia. 

.Area 

fir. 

Dia. 

Area 

Cir. 

Dia. 

Area 

Cir 

Dia. 

Area 

Cir. 


0 0123 

.3926 

10 

78.54 

31 41 

30 

706.86 

94 25 

65 

3318.3 

204.2 

M 

0.0 ‘91 

.7854 

V 

86.59 

32.99 

31 

754.77 

97 39 

66 

3421.2 

207.3 

Vs 

0.1104 

1 178 

11 

95.03 

34.5? 

32 

804 25 

100.5 

67 

3525.7 

210.5 

Vi 

0.1963 

1 570 

Vi 

103.87 

36 13 

33 

855.30 

103.6 

68 

3631 7 

213 6 

Vs 

0.3067 

1.963 

12 

113.10 

37.70 

34 

907.92 

106.8 

69 

3739 3 

216.8 

Vi 

0.4417 

2.356 

Vi 

122.72 

39.27 

35 

962.11 

109.9 

70 

3848.5 

219.9 

Vs 

0.6013 

2.748 

13 

132.73 

40 84 

36 

1017.9 

113.1 

71 

3959 2 

223.1 

l 

0.7854 

3.141 

K 

143 14 

42 41 

37 

1075.2 

116.2 

72 

4071.5 

226 1 

Vs 

0 9940 

3.534 

u 

153.94 

43.98 

38 

1134.1 

119.4 

73 

4185.4 

229.3 

H 

1.227 

3.927 

Vi 

165.13 

45 55 

39 

1194.6 

122.5 

74 

4300.8 

232.5 

Vs 

1.485 

4 320 

15 

176.71 

47 12 

40 

1256.6 

125.7 

75 

4417.9 

235.6 

V 

1.767 

4.712 

Vi 

188.69 

48.68 

41 

1320.3 

128.8 

76 

4536.5 

238.7 

Vs 

2.0 7 4 

5 105 

16 

201.06 

50.26 

42 

1385.4 

131 9 

77 

4656 6 

241 9 

Vi 

2.405 

5.498 

Vi 

213.82 

51.83 

43 

1452.2 

135.1 

78 

4778.4 

245.0 

Vs 

2.761 

5.890 

17 

226.98 

53.41 

44 

1520 5 

138.2 

79 

4901.7 

248.2 

2 

3 141 

6.283 

Vi 

240 53 

54.98 

45 

1590.4 

141 4 

80 

5026.5 

251.3 

Vi 

3 976 

7.069 

18 

254.47 

56.65 

46 

1661.9 

144 5 

81 

5153.0 

254.5 

}/% 

4.909 

7.854 

Vi 

268.80 

58.12 

47 

1734.9 

147.7 

82 

5281 0 

257.6 

Vi 

5.940 

8 639 

19 

283.53 

59.69 

48 

1809.5 

150 8 

83 

5410.6 

260.7 

3 

7.069 

9.425 

Vi 

298.65 

61 26 

49 

1885.7 

153.9 

84 

5541 8 

263 9 

Vi 

8.296 

10 21 

20 

314.16 

62.85 

50 

1963 5 

157 1 

85 

5674.5 

267.0 

Vi 

9.621 

11 00 

Vi 

330.06 

64.40 

51 

2042.8 

160.2 

86 

5808 8 

270.2 

Vi 

11 045 

11.78 

21 

346.36 

65.97 

52 

2123.7 

163 4 

87 

5944 7 

273.3 

4 

12.566 

12.57 

Vi 

363 05 

67.54 

53 

2206.1 

166.5 

88 

6082.1 

276.5 

V 

15.904 

14.14 

22 

380.13 

69.11 

54 

2290.2 

169.6 

89 

6221 1 

279.6 

5 

19.635 

15.71 

Vi 

397.61 

70.69 

55 

2375.8 

172.8 

90 

6361.7 

282.7 

Vi 

23.758 

17.28 

23 

415.48 

72.26 

56 

2463.0 

175.9 

91 

6503.8 

285.9 

6 

28.274 

18.85 


433.74 

73.8? 

57 

2551.8 

179.0 

92 

6647.6 

289.0 

Vi 

33 183 

20 42 

24 

452.39 

75.40 

58 

2642.0 

182.2 

93 

6792 9 

292.2 

7 

38 485 

21.99 

Vi 

471.44 

76.97 

59 

2734.0 

185.4 

94 

6939 8 

295 3 

u 

44 179 

23.56 

25 

490.87 

78.54 

60 

2827.4 

188.5 

95 

7088.2 

298.4 

8 

f0.265 

25.13 

26 

530 93 

81 68 

61 

2922.5 

1916 

96 

7238.2 

SOI. 6 

V 

56.745 

26.70 

27 

572.50 

84.82 

62 

3019.1 

194.8 

97 

7389.8 

304 7 

9 

63 617 

28.27 

28 

615.75 

87.96 

63 

3117.2 

197.9 

98 

7543.0 

307 ? 

Vi 

70.882 

29 84 

29 

660 52 

91 11 

64 

3217 0 

201 1 

99 

7697.7 

311 f 


















































































72 


THE GENERAL ENGINEERING COMPANY 


International Atomic Weights 

From Smithsonian Table—1916 


Element 

Symbol 

Atomic 

Weight 

Valence 

Aluminum. 

A1 

27.1 

3 

Antimony. 

Sb 

120.2 

3, 5 

Argon. 

A 

38.88 

0 

Arsenic. 

As 

74.96 

3, 5 

Barium. 

Ba 

137.37 

2 

Bismuth. 

Bi 

208.0 

3, 5 

Boron. 

B 

11.0 

3 

Bromine. 

Br 

79.92 

1 

Cadmium. 

Cd 

112.40 

2 

Caesium. 

Cs 

132.81 

1 

Calcium. 

Ca 

40.07 

2 

Carbon. 

C 

12.00 

4 

Cerium. 

Ce 

140.25 

3, 4 

Chlorine. 

Cl 

35.46 

1 

Chromium. 

Cr 

52.0 

2, 3, 5 

Cobalt. 

Co 

58.97 

2, 3 

Columbium [Niobium]. 

Cb 

93.5 

3, 5 

Copper. 

Cu 

63.57 

L 2 

Dysprosium. 

Dy 

162.5 

3 

Erbium. 

Er 

167.7 

3 

Europium. 

Eu 

152.0 

3 

Fluorine. 

F 

19.0 

1 

Gadolinium. 

Gd 

157.3 

3 

Gallium. 

Ga 

69.9 

3 

Germanium. 

Ge 

72.5 

4 

Gluciniun. 

G1 

9.1 

2 

Gold. 

Au 

197.2 

1, 3 

Helium. 

He 

3.99 

0 

Holmium. 

Ho 

163.50 

3 

Hydrogen. 

H 

1.008 

1 

Indium. 

In 

114.8 

3 

Iodine. 

I 

126.92 

1 

Iridium. 

Ir 

193.1 

4 

Iron. 

Fe 

55.84 

2, 3 

Krypton. 

Kr 

82.92 

0 

Lanthanum. 

La 

139.0 

3 

Lead. 

PI) 

207.10 

2, 4 

Lithium. 

Li 

6.94 

1 

Lutecium. 

Lu 

174.0 

3 

Magnesium. 

Mg 

24.32 

2 

Manganese. 

Mn 

54.93 

2, 3, 7 

Mercury. 

Hg 

200.6 

1, 2 

Molybdenum. 

Mo 

96.0 

4, 6 

Neodymium. 

Nd 

144.3 

3 

Neon. 

Ne 

20.2 

0 

























































CONSULTING ENGINEERS 


73 


International Atomic Weights—Cont 


Element 

Symbol 

Atomic 

Weight 

Valence 

Nickel. 

Ni 

58.68 

2,3 

Niton. 

Nt 

222.4 

Nitrogen. 

N 

14.01 

3, 5 

Osmium. 

Os 

190.9 

6, 8 

Oxygen. 

0 

16.0 

2 

Palladium. 

Pd 

106.7 

2, 4 

Phosphorus. 

P 

31.04 

3, 5 

Platinum. 

Pt 

195.2 

2, 5 

Potassium. 

K 

39.10 

1 

Praseodymium. 

Pr 

140.6 

3 

Radium. 

Ra 

226.4 

2 

Rhodium. 

Rh 

102.9 

3 

Rubidium. 

Rb 

85.45 

1 

Ruthenium. 

Ru 

101.7 

6, 8 

Samarium. 

Sa 

150.4 

3 

Scandium. 

Sc 

44.1 

3 

Selenium. 

Se 

79.2 

2, 4,6 

Silicon. 

Si 

28.3 

4 

Silver. 

Ag 

107.88 

1 

Sodium. 

Na 

23.00 

1 

Strontium. 

Sr 

87.63 

2 

Sulphur. 

S 

32.07 

2, 4,6 

Tantalum. 

Ta 

181.5 

5 

Tellurium. 

Te 

127.5 

2, 4, 6 

Terbium. 

Tb 

159.2 

3 

Thallium. 

T1 

204.0 

1,3 

Thorium. 

Th 

232.4 

4 

Thulium. 

Tin 

168.5 

3 

Tin. 

Sn 

119.0 

2,4 

Titanium. 

Ti 

48.1 

4 

Tungsten. 

W 

184.0 

6 

Uranium. 

U 

238.5 

4, 6 

Vanadium. 

V 

51.0 

3, 5 

Xenon. 

Xe 

130.2 

0 

Ytterbium. 

Yb 

173.0 

3 

Yttrium. 

Yt 

89.0 

3 

Zinc. 

Zn 

65.37 

2 

Zirconium. 

Zr 

90.6 

4 



















































74 


THE GENERAL ENGINEERING COMPANY 


Foreign Coins 

VALUES IN UNITED STATES CURRENCY 

(Authorized by the Secretary of the Treasury of the U. S., Oct. 1, 1920) 


All money in gold unless marked: (s), silver standard, or (gs) 
gold and silver standard. 


Country 

Coin 

Standard 

Monetary 

Unit 

Value 

U. S. Gold 
Dollars 

1920 

North America 



Canada. 

Dollar 

$1.0000 

Cuba. 

Peso 

1.0000 

Haiti. 

Gourde 

0 2500 

Santa Domingo. 

Dollar 

1.0000 

New Foundland. 

Dollar 

1.0000 

Mexico. 

Peso 

0.4985 

Central America 



Costa Rica. 

Colon 

0.4653 

Guatemala. 

Peso [s] 

0.6864 

Honduras. 

Peso [s] 

0.6864 

British Honduras. 

Dollar 

1.0000 

Nicaragua. 

Cordoba 

1.0000 

Salvador. 

Colon [s] 

0.5000 

Panama. 

Balboa 

1.0000 

South America 



Argentina. 

Peso 

0.9648 

Bolivia. 

Boliviano 

0.3893 

Brazil. 

Milreis 

0.5462 

Chile. 

Peso 

0.3650 

Columbia. 

Dollar 

0.9733 

Ecuador. 

Sucre 

0.4867 

Paraguay. 

Peso 

0.9648 

Peru. 

Libra 

4.8665 

Uruguav. 

Peso 

1 0342 

Venezuela. 

Bolivar 

0 1930 

Europe 



Austria. 

Krone 

0.2026 

Belgium. 

Franc [gs] 

0.1930 

♦Czechoslovakia. 

♦Crown 

*0.203 

Denmark. 

Krone 

0.2680 

Finland. 

Markka 

0.1930 

France. 

Franc [gs] 

0.1930 

Germany. 

Mark 

0.2382 

Great Britian. 

Pound Sterling 

4.8665 

(Including Br. Colonies in Aus. & Af.) 


Greece. 

Drachma [gs] 

0.1930 

Netherland [Holland]. 

Guilder [Florin] 

0.4)20 

Italv. 

Lira [gs] 

0.1930 

*Jugo-Slavia. 

♦Crown 

*0.203 

Norwav. 

Krone 

0.2680 

♦Poland. 

♦Mark 

*0.238 

Portugal. 

Escudo 

1.0805 

Roumania. 

Leu 

0.1930 

Russia .| 

Ruble 

0.5146 


Values obtained from other sources than U. S. Treasury. 

























































CONSULTING ENGINEERS 


75 


Foreign Coin—Cont. 


Country 

Coin 

Standard 

Monetary 

Unit 

Value 

U. S. Gold 
Dollars 

1920 

Serbia. 

Dinar 

0.1930 

Spain. 

Peseta [gs] 

0.1930 

Sweden. 

Krona 

0.2680 

Switzerland. 

Franc 

0.1930 

Turkey. 

Piaster 

0.0440 

Africa 



Egypt. 

Pound 

4.9431 

Liberia. 

Dollar 

1.0000 

British Colonies. 

Pound Sterling 

4.8665 

Asia 



India. 

Rupee 

0.3244 

Indo-China. 

Piaster [s] 

0.7413 

Japan . 

Yen 

0.4985 

Persia. 

Achrefi [g] 

0.0959 


Kran [s] 

0.1264 

Phillipines. 

Peso 

0.50000 

Siam. 

Tical 

0.3709 

Straits Settlements. 

Dollar 

0.5678 


Tael [s] 

1.0278 

China. 

Tael [s] 

to 1.1449 


Dollar [s] 

0 7374 


Dollar [sj 

to 0.7455 


(Note—Chinese money varies in value between various ports) 



























76 


THE GENERAL ENGINEERING COMPANY 



Graphite Flotation Plant 

Carbon Mountain Graphite Company, Lineville, Ala. 
Designed and built by the General Engineering Company 















CONSULTING ENGINEERS 


77 


INDEX 

METALLURGICAL BULLETIN 

Page 

Altitude Effects . 52 

Assaying . 13 

Atomic 'Weights . 72-73 

Ball Mills, conical . 57 

Ball Mills, cylindrical . 57 

Barometric Pressure at altitudes . 52 

Belt Conveyors . 62 

Belt Screens, Callow . 59 

Blake Crushers . 55 

Blowers, Flotation . 61 

Boiler Capacities, Coal Consumption . 45 

Boiling Points at altitudes . 52 

Breakers, Blake and Gyratory . 55 

Bucket Elevators, Belt-and . 63 

Callow Screens . 59 

Callow Settling Tanks . 60 

Centrifugal Force . 53 

Charges for Ore-Testing . 13 

Charges for Erection, Operation . 25 

Chemical Elements, properties . 72-73 

Chilean Mills . 56 

Circles, Circumferences and Areas . 71 

Circulating Feed . 50 

Classifiers, Hydraulic . 60 

Coal Consumption, Dryers . 62 

Coal Consumption, Steam Plants . 45 

Coins, Foreign, value of . 74-75 

Concentration, Milling costs . 32, 33, 36 

Erection costs . 42 

Power required . 42 

Water required . 47 

Flow Sheets . 16-20 

Consulting work . 15 

Conveyors, Belt . 62 

Copper Production, Smelter . 29 

Refinery balance sheet . 30 

by states . 29 

Copper Minerals . 66 et seq. 

Costs . 32-42 

Crushing, costs ... 36 

divisions or classification of . 36 

Power required . 42 

Crushers, Blake, Gyratory, Disc . 55 

Crushing Machinery ..*. 55-58 

Cyanidation, Milling costs . 34, 35, 37 

Erection costs . 42 

Power required . 42 

Water required . 47 

Flow-sheet of mill . 21 

Design of Plants . 23-25 

Disc Crushers .<. 55 






















































78 


THE GENERAL ENGINEERING COMPANY 


index-continued 


Page 


Dredging, costs . 

Dryers, Cylindrical, power . 

Drying Ores . 

Electricity, Costs of Power . 

Units and Relations . 

Current in circuits . 

Power in circuits . 

Power Transmission . 

Elements, Chemical . 

Elevators, Belt-and-Bucket . 

Engines, Steam, Types, water and coal consumption 
Equivalents of Weights and Measures . 


Falling Bodies, formulae . 53 

Fees, Ore Testing . 13 

Erection, Operating . 25 

Filtering Concentrates . 60 

Filters, Vacuum . 60 

Flotation, Pneumatic . 61 

Testing Equipment . 7, 10 

Blowers . 62 

Milling costs . 33, 36 

Flow-sheets of mills . 15-21 

Force, Centrifugal, Gravity . 53 

Foreign Coins, value of . 74, 75 

Gold Production . 28 

Gravity, Falling Bodies . 53 

Gyratory Crushers .’. 55 

Hardinge Mills . 57, 58 

Hartz Jigs . 61 

Hydraulic Classifiers . • 60 

Induction Motors, current . 46 

Information required for ore testing . 11, 12 

Jigs, Hartz . 61 

Kilowatt-hours-per-Ton . 43 

Laboratory, Plans . insert 8, 9 

Leaching Copper, costs . 37 

Lead Minerals . 67 et seq 

Production . 31 


28-29 

43 

43 

44 

44 
72-73 

63 

45 
51 


M easures . 51 

Metallurgical Tests . 9, 11 

Metal Statistics . 28-30 

Milling Costs . 32-37 

Milling Machinery . 54-63 

Mills, Ball . 57 

Chilean . 56 

Pebble (Tube) . 58 

Stamp . 57 

Flow-sheets of . 15-21 

Representative, designed and constructed by the General 

Engineering Company . 26, 27 


i 


v r ( 






















































CONSULTING ENGINEERS 79 


index-continued 

Page 

Mine Examination . 8 

Minerals, Principal Economic . 66-68 

Minerals, List of . 69-71 

Minature Ore-Testing Plant .i. 14 

Money, value of Foreign Coins . 74-75 

Motors, Current . 43 46 

Multipliers ... 46, 47,’ 52 

Operation of Plants ... 23, 25 

Ore Testing . 9-14 

Pebble Mills, conical and cylindrical . 58 

Pilot Plants . 11 

Piping in Mills, Water . 48 

Plants constructed by General Engineering Company, illustrated. 

Cons. Copper Mines Co., . 27 

C. C. Cunningham . 22 

Magna Copper Company . 25 

National Copper Company . 23 

Dominion Molybdenite Company . 54 

Utah-Apex Mining Company . 24 

Utah Consolidated Mining Company . 40-41 

Pneumatic Flotation . 61 

Power, Costs . 38, 39 

Electrical Transmission . 44 

in Electrical Circuits . 43 

Mill Horse Power . 42 

Units and Relations . 43 

Pressures, Multipliers . 52 

Pulp Calculations . 48 

Pulp Density Relations . 49 

Pump, Vacuum, capacity for filtering . 60 

Quantity of Ore for Tests . 13 

Ratio of Concentration, Formulae . 50 

Recovery, Formulae . 50 

Rolls, Crushing . 56 

Rod or Roller Crushing Mills . 7 

Sale of Ore for Clients . 8 

Screens, Revolving, Trommels . 59 

Impact . 59 

Belt, Callow . 59 

Conversion formulae . 59 

Shipments of samples for testing . 13 

Silver Poduction . 28 

Silver, economic minerals . 67 

Specific Gravity, definition . 47 

of Minerals . 66-71 

Stamp Mills . 57 

Steam Plants . 45 

Surface, tables . 51 

Tables, Concentrating . 60 

Tanks, Callow Settling . 60 

Thickening . 60 






















































80 


THE GENERAL ENGINEERING COMPANY 


index-continued 

Page 

Testing of Ores, classes of tests . 9-11 

Timbers, strength of . 64, 65 

Trommel Screens . 59 

Tube (Pebble) Mills . 58 

Vanners, Frue . 60 

Water, Constants . 46-47 

Water Piping in Mills. 48 

Weights and Measures . 46-52 

Wiring Table-Copper Wire, for Electricity . 44 

Wooden Beams, strength of . 65 

Columns, strength of . 64, 65 

Zinc Production . 31 

Zinc, economic minerals . 68 





















